>> if there's something that the sober world can teach everyone else, it's that dignity and respect, when it's sprinkled on human beings, is the most powerful drug that we possess. a tough assistant d.a. gunned down. but wasn't over. the dead man's boss and his wife were next. >> whoever went in there had a mission. >> did you think there was a list? >> oh, sure. >> i don't think there is any doubt that this is a serial killer. >> someone had declared war on law enforcement and their families. >> unless you know it's me, be ready to use it.

>> the trail would stretch from coast to coast. >> is this an ablt government mill he sha militia group? >> before leading investigators back home. >> was he laifg double life? >> i think he was. >> you're making him sound like hannibal lechter. >> reporter: the courthouse. the moral center of every american city and town. the place we go to settle differences, resolve disputes, find justice. it's the place where the story usually ends. but not this time. not in rural kaufman, texas,

where life is leisurely and no one is a stranger. >> oh my god. someone just shot someone. they're laying on the ground. >> just, "bam, bam, bam." >> reporter: it's where the story begins. >> somebody was tryin' to send a message. it was just so bold. >> reporter: a story that quickly got too big for this texas town and like a prairie fire, spread across the nation. >> we have some new information this morning on the manhunt for a killer who gunned down a district attorney. >> may have been involved in the brazen murder of the head of colorado's prison. >> reporter: in this tale, the hunters became the hunted. >> that's what was so scary. it's not just me anymore. i have young kids. my husband, my family. >> my wife had two guns out, and i said, "unless you know it's me coming through the door, be ready to use 'em." >> reporter: shannon hebert never expected to be in danger

when she started the career she always wanted, practicing law. >> why did you wanna be a lawyer? >> my gosh, in second grade a judge came to my class and i fell in love with that, and i wanted to be a judge or a lawyer. >> her dream came true. >> i was the first one to go to college. >> reporter: by 2008, shannon had passed the bar exam and got her first job, as a prosecutor at the kaufman county district attorney's office, on the second floor of the courthouse in the center of town. >> i loved the office. the people around me were so knowledgeable. they were almost all from dallas. >> reporter: one of those lawyers from dallas, mark hasse an experienced prosecutor, a guy who lived his job. >> did you learn anything from him? >> oh, gosh, yes, of course. we would go to mark for almost everything. >> reporter: that's because mark had prosecuted some of the worst criminals in texas. >> he was tenacious. he was an intellectual. and he was very quick on his feet.

alawyer with the department of justice. back in the 80s, he and mark hasse were young guns working in the organized crime section of the dallas da's office. >> mark was not afraid of taking on a fight. some of the defendants on some of the cases were -- were very bad people. and mark had the personality to stand in the breach and prosecute the worst of the worst. >> why did mark move out of dallas? >> he wanted a place where he had some room, so he bought a house on about eight acres. built a barn out there. he just loved being around animals and he loved the space. >> reporter: besides animals and wide-open spaces, mark had another passion -- flying. back in 1995, it almost killed him. >> mark did have a bad accident. >> mark had a terrible accident. >> a high flying commemoration of world war ii's end, 50 years ago this month. >> reporter: mark was part of this aerial armada of vintage planes when something went terribly wrong. >> he believed the engine had failed. and he made a forced landing.

ran off the end of the runway. he survived, but he had a very severe brain injury. >> did he decide to fly again at any point? >> he did. >> why do you think he wanted to fly again? he almost died. >> it's like being thrown from a horse. he wanted to be the person that he was before. >> he did it. >> he did. he did. but it took a long, long time. >> reporter: mark's colleagues in the da's office admired mark's strength to fight through adversity. but they also got a kick out of his weakness -- his love for sugary snacks. >> he had a sweet tooth, and he would mostly eat everyone's stuff. so, like, we would have weekly prosecutor meetings every monday, and we would get doughnuts for them. and he would -- he would always get there first and steal my blueberry doughnut. we -- we both loved that. >> reporter: in 2011, mark and shannon got a new boss who seemed to fit right in with their office family, the newly-elected district attorney, mike mclelland. >> my name's mike mclelland. i'm the criminal district attorney for kaufman county. >> reporter: mike's

>> reporter: mike's step-daughter, christina foreman, says he loved the job. >> i think he really did embrace the role as a leader. and he enjoyed the people he worked with. and he would talk about, you know, "oh, this person did this. and i was really proud of them and this person did this and i was really proud of them. >> everything was new to him. he came in and just took it over. >> was he tough? >> i wouldn't say he was tough on us at all. the greatest thing about him was that he let us do what we do best. >> reporter: and mike quickly formed a bond with mark hasse, the experienced prosecutor and the head of the felony unit. >> mark was his best friend in the office. they were very close. >> reporter: mikes' wife, cynthia, fit right in around the office too. she was almost like a den mother. she worked as a nurse, but found time to bake cakes and cookies for the staff. cynthia was also an avid quilter, who loved making gifts for her husband's co- workers, including shannon, now married with two children. >> she would bring fabrics in to show me, you know, "is this going to match the nursery?" and then she quilted it for me. it was just stunning. it was very beautiful. >> reporter: and that's how it was -- a happy, humming office in a quiet small town. until january 31st, 2013 just

before 9 a.m. at that moment, the calm, serene morning and the lives of everyone in the da's office would be shattered. >> i heard what i thought to be gunshots. >> reporter: police officer jason stastny was a few blocks from the courthouse. he and his partner were investigating a burglary when something big caught his attention. >> it was just a slow and methodical five shots. it was just, "bam, bam, bam, bam, bam." and -- and it was a little pause, i guess you'd say, and then three more shots after that. >> reporter: shannon was inside the courthouse when she heard the sound of sirens. >> that's not unusual because there's a police station just a block away. there's a hospital a few blocks down the street. >> reporter: that siren was jason stastny's squad car. >> you know, i -- i hollered at my partner.

i said, "hey, you know, those are gunshots. we need to go. we need to go." so, we packed up real quick, hopped in the car -- >> reporter: the car camera was rolling as he and his partner drove toward the gunshots. >> -- about halfway over a dispatcher came across the radio and told us that -- that a man had been shot and gave us the location. >> kaufman county 911. >> yes. we've got a gentleman on grove street and madison that just got shot. >> reporter: that's just a block from the courthouse. shannon noticed that her secretary was looking out the window at some commotion on the street. >> my secretary turned around and she was crying. initially, i just wanted to comfort her. i couldn't even imagine what she was crying about and when she turned from the window. all she said was, "it's mark." >> reporter: mark hasse, her friend and colleague. >> and my natural instinct was, "did he get hit by a car?" and she was, like, "no, shannon, he was shot." >> who is it? >> it's mark hasse. oh, my god, it's mark hasse. he's an assistant district attorney.

it stunned onlookers and police. who would even attempt such a brazen attack? >> did that tell you these two knew each other? >> that seemed very personal to me. protect your pet with the #1 name in flea and tick protection. frontline plus. trusted by vets for nearly 20 years. you have power over pain, so the whole world looks different.

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talk to your doctor about chantix. >> reporter: a beloved prosecutor, mark hasse, had just been shot outside the courthouse in kaufman, texas during the morning rush. >> 9024, check. >> reporter: officer jason stastny was one of the first on the scene. >> when i pulled up, i saw a man. he was laying here in the street. >> reporter: you're seeing the dramatic images from officer stastny's on-board

camera. >> jason driving with meade under dash-cam video. and there was a woman that was over him. looked like she was doin' cpr. >> reporter: that woman had witnessed the shooting from her car, saw the shooter flee, then tried to help mark. now, stastny was taking over, going on instinct and adrenaline. >> this was one of those scenes when you pull up, it's nothing you -- you could prepare for. >> reporter: he knew right away it was bad. >> he's got a shot in his face. >> he looked at me and then he stopped breathin'. that's when i started cpr. >> there you go. there you go, buddy. keep breathing for me. >> i got him to take seven breaths. i do remember that. >> reporter: as his car-cam kept rolling, stastny's body mic picked up his pleas for mark to hold on just a little longer. >> get you another breath, mark. come on. e.m.s. is almost here. the ambulance is coming. >> you know, i tried my best to tell him, you know. you're doing good. you're doing good. keep breathing. the ambulance is coming. >> reporter: officer stastny had been at the scene for five agonizing minutes when the ambulance rolled up. >> anyone know anything about

him? >> he's one of the d.a prosecutors. >> reporter: back at the courthouse, shannon hebert was getting updates on mark. >> i don't really know how many minutes passed by when another prosecutor came into the courtroom saying how bad it was. >> reporter: about an hour earlier, shannon had walked from the parking lot to the courthouse. that's the same route her friend and colleague, mark hasse, was walking when he was shot. now, too afraid to go anywhere, she stayed inside praying for him. >> we are now just waiting to hear if he's gonna live. >> reporter: but bad news traveled fast. >> it didn't take very long for his trial partner to walk into the courtroom shaking her head and crying. and i think at that point we knew he was gone. >> i can only imagine how horrible a moment like that is. >> it's horrible. it will -- it will be in my brain forever. like i'll never, ever forget that. >> there's not a day that goes by that i don't go by here and -- and think back to that day, and exactly what happened, and exactly what i saw.

>> mark hasse was dead at 57, gunned down on his way to work, a block from the courthouse. >> people in kaufman are shocked by the deadly attack out in the open in the town square. >> i just never in a million years would have expected one of our prosecutors, much less somebody i knew personally, to be laying on the ground dead. >> with one of their own down, lt. jolie stewart, from the county sheriff's department, quickly joined the swarm of law enforcement jumping on the case. >> we didn't have time to grieve about it. we didn't have time to talk about our feelings. it was time to go to work. >> reporter: lt. stewart and others canvassed the area but solid information was hard to come by. witnesses said the shooter hopped into the passenger side of the getaway car as it sped away. so there had to be at least two people involved. they also said the car was silver -- or was it gray or tan?

a four-door, maybe a ford taurus. but with no license plate. >> the rest of that day we were just going around looking for, you know, the car. >> i don't think i've ever noticed how many silver or light-colored, four-door sedans there are. >> reporter: and, even though the killer had brazenly attacked during the morning rush, witnesses said he covered up. >> one of the witnesses described him as wearing a hoodie that was black and covered their face. and then, another person who saw him from a distance said, you know, all black, you know, dark clothing. >> reporter: but there was something more. a witness in a garage right across the street heard the victim's last words. >> mark said, "no, no, i'm sorry." and that was it. and that was after a little bit of kind of a shoving match. >> did that tell you that these two knew each other? >> that seemed very personal to me. >> reporter: no weapon was found

at the scene, and no shell casings either. >> did that tell you anything that there were no shell casings? >> yes, it told us there was gonna have to be a revolver. >> reporter: that's because revolvers keep bullet casings inside the gun after firing. >> i can only imagine how terrified mark must have been in those final moments. >> mark was doing what he did every day. just going to work. >> reporter: now, his fellow prosecutors feared he died for that work. and they could be next. no one felt safe. >> all of us were scared. we didn't know if there was a bunch of people waiting to try to shoot us. >> reporter: the courthouse was locked down in the morning then closed for the day. prosecutors and office staff were given extra security. >> they were walking us to our cars carrying huge rifles and guns. >> when did it start to sink in for you that this could've been me? you walk into work with mark. your office is right there. >> i think that was the immediate fear.

it could have been any of us. >> we lost a really, really good man. >> district attorney mike mclelland stood tall when he addressed the media about the killing of his good friend. >> i hope that the people that did this are watching. because we're very confident that we're gong to find you. we're going to pull you out of whatever hole you're in. we're gonna bring you back and let the people of kaufman county prosecute you to the fullest extent of the law. >> reporter: mike's step-daughter, christina, watched his take-no-prisoners press conference with immense pride. >> that's not an unusual thing for him. he -- you know, when he really, truly felt deeply about something, then he was going to make a stand for it. he was gonna make a stand with his beliefs and really try to do the right thing. >> reporter: but bringing this killer or killers to justice would take a lot more than tough talk. this was just the start of a

crime spree that would terrorize the very people who protect us. now, no one was safe. >> reporter: coming up -- that investigation would also present an overwhelming challenge, thanks to a suspect list including the hundreds of defendants mark had put away. >> i immediately started to think about the organized crime cases, and the murder cases. many of those people were starting to parole out. >> any one in particular stick out in your head? >> reporter: when dateline continues. whoa, this is awful, try it. oh no, that looks gross what is that? you gotta try it, it's terrible. i don't wanna tray it if it's terrible. it's like mango chutney and burnt hair. no thank you, i have a very sensitive palate. just try it! hey guys, i think we should hurry up. if you taste something bad, you want someone else to try it. it's what you do. i can't get it out of my mouth! if you want to save fifteen percent or more on car insurance, you switch to geico. it's what you do. dog, dog, dog.

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>> i mean we really did love him. it -- it was devastating when he was gone. >> reporter: monday morning, four days after the murder of mark hasse, fellow prosecutor shannon hebert returned to work with a heavy heart. >> of course it was a hard monday at our weekly meeting without mark. our whole office was devastated. i mean, his door was closed. >> reporter: security remained tight in and around the courthouse. the people inside took on a bunker mentality. >> folks are trying to deal with what happened. nobody's ever done this before. it's new territory for everybody. >> reporter: his colleagues were terrified, and many wanted to carry guns for protection.

district attorney mike mclelland made it easier for everyone to get concealed handgun licenses. >> we could take the course for free, and we could -- start getting our handgun license, just in case we needed it. >> did you get a gun? >> no, i didn't. >> did you think about it? >> oh, yeah. i definitely wanted to get one. i didn't -- i don't think i woulda carried it every day, but i definitely wanted to be able to use one. >> reporter: it's the kind of thing people do when they're scared and panicked, the justice system under attack. the murder brought an all-star army of law enforcement to the case. the sheriff's training center was turned into a command post. it was soon buzzing with local police, texas rangers and federal agents from the atf and fbi. >> that was what's amazing about this case, is you had federal, state -- law enforcement all working together -- in a team. >> reporter: advising this team, toby shook and bill wirskeye, veteran, high-profile attorneys from dallas who were quickly named special prosecutors. >> once you get over the initial shock and disbelief that a prosecutor and someone that you know has been murdered, kind of your professional training kicks in.

and that's where toby and i stepped up and volunteered to help them in that role. >> reporter: the crime seemed to be what every prosecutor fears, a revenge hit for putting away a bad guy. that struck a chord that reverberated from kaufman to dallas, throughout texas and beyond. >> i think every judge, every defense attorney, every prosecutor has that in the back of your mind. so that just brought all those fears to the forefront for everyone in the criminal justice system. >> does it send a chill through everyone when one of your own is killed like that? >> it does. i mean, whoever did this obviously crossed a line that other people just rarely even approach. and it starts making you think of what you do for a living and your family members and your own personal safety. >> reporter: the initial theories were as numerous as the hundreds of cases mark hasse had prosecuted, and the first place to look was right in kaufman county, where mark was a felony prosecutor for three years. >> the big questions that we had

is who's he prosecuted recently? >> reporter: sheriff's investigator jolie stewart was involved from day one. >> is there something recent that he's prosecuted that's got somebody upset? so we started delving off into his caseload. >> reporter: investigators looked into every local case mark had prosecuted. there were robberies, drug prosecutions and even a theft that involved an elected official who stole office equipment. they didn't immediately find anything that led them to a suspect. u.s. marshals pulled in anyone with an oustanding arrest warrant. nothing there either. so, the task force widened the scope of the investigation beyond kaufman. >> we don't have a lot of violent crimes in kaufman. i mean, especially murders. so we just kind of naturally assumed it was someone from dallas. >> reporter: dallas, the big city less than 30 miles, but seemingly a lifestyle away. remember, back in the 1980s, mark and fellow prosecutor marcus busch locked up some pretty tough customers there. >> i immediately started to

think about the organized crime cases and the murder cases that we'd all prosecuted. many of those people received life sentences and were starting to parole out. >> someone just held this grudge, got out of prison and just wanted him. it was just a personal vendetta against mark. >> reporter: even though investigators were convinced he was murdered because of his job as a prosecutor, they didn't stop there. >> you still have to interview friends, family members, associates. mark was a teetotaler, he wasn't married and he didn't have any children. those extensive checks into his background came up empty. >> there just wasn't anything there. he loved his mother who lived in dallas and spent a lot of time taking care of her and taking her to dinner. >> reporter: all the initial checks into mark's personal and professional life were not panning out. frustration was setting in, because cases get harder to solve after the first 48 hours. two full days in, mark's murder had reached that crossroad, and investigators were searching

desperately for a break. >> insiders tell us tonight there are simply no promising leads in this case right now. his murder is turning into a real who-dunnit. >> any assistance that anyone can give us in finding the people who did this will be greatly appreciated. >> reporter: d.a. mclelland had it particularly tough. he had an office to run while mourning a good friend. >> how hard was it for mike to come back to the office after the shooting? >> with mark's door closed, and his buddy gone, it was very difficult. he talked a lot about the case. >> shot here at his front door. >> reporter: and the case was about to get a lot bigger with another brazen murder, only this one crossed another line, a very sacred line. >> reporter: coming up -- another member of law enforcement, gunned down. had the killer struck again? when "dateline" continues.

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frontline plus. vo:untrue attacks againstve, mike bloomberg. bloomberg has been praised by president obama. obama: he's been a leader

throughout the country for the past twelve years. mr. michael bloomberg is here. vo: mike worked with president obama to combat gun violence and improve public education. as president, he'll work to combat inequality by launching a new initiative to spur african american and latino homeownership and small business growth. and he'll beat the divider in chief. bloomberg: i'm mike bloomberg and i approve this message.

hello. here's what's happening. breaking news out of asia. south korea's military claims pyongyang fired two projectiles along the coast. so far it is under known whether they were rockets and missiles and how far they traveled from north korea. and on the heels of pete buttigieg ending his run, amy klobuchar was forced to ka ed da rally in dallas. now back to "dateline." >> an emotional afternoon in kaufman county where hundreds of people attended a memorial service for slain prosecutor mark hasse. >> he was constantly begging for more of my wife's cookies. >> reporter: d.a. mike mclelland. >> she makes cookies for the office about once a month, and he would run out in about 12 minutes. >> reporter: mark's longtime friend, marcus busch, also memorialized him.

>> this world is a better place because of mark, and so are we. the world lost a good man. somebody who was resolute. always knew the difference between right and wrong and would fight for that. >> reporter: now, special prosecutors, toby shook and bill wirskeye along with a multi-agency task force were fighting for mark, searching for his killer but not coming up with easy answers. because he was so close to his friend and employee, d.a. mike mclelland had to bow out of the investigation. he and his co-workers were doing what they could, opening their files to investigators. >> everything anybody can think of, they're looking through it. >> reporter: checks into mark's personal background had gone nowhere. so the task force continued to look at his professional cases from 30 years ago to the week before, but it was slow going. >> and how do you sift out, well, it couldn't have been this person, but maybe it was this

person? >> first of all, you see if they're still locked up. you see where they are, their whereabouts. you see is there anything unusual or specific about a case that would give someone cause to have a grudge. >> reporter: four weeks into the investigation, a tip came into the county crime- stoppers' anonymous tip-line that looked a big break. >> the tipster said that they'd been in a bar, in a small town in kaufman. and overheard two -- two white males talkin' about the hasse killing, and taking responsibility for it. >> reporter: the tip lacked the kind of detail that investigators needed to follow up. and, using the crime stoppers system, the tipster remained anonymous. if this was going to be the game-changer, investigators would need lots more information or a little more luck. >> you're still hoping for the big break and maybe a luck -- lucky traffic stop or somebody's gonna -- that knows about this murder is gonna pick up the phone and call in and that'll be the magic phone call. >> reporter: there was something that might lead them to the

killer, the way mark had been murdered. the killer had been lying in wait. mark was shot at point-blank range, execution style. all this led investigators to think this could be an organized crime hit. >> rumors are sweeping the town. talk of mexican drug cartels and prison gangs. >> we're open to every avenue right now. >> reporter: nbc's channel five in dallas covered the hasse case from the beginning, and reporter ken kalthoff was there for it all. >> mexican drug cartels were suspect immediately because of the fact that hasse had been involved in drug cases over the years. >> reporter: and investigators also suspected another group, less publicly known but very dangerous, the aryan brotherhood of texas, a prison gang of white supremacists. >> why was the aryan brotherhood a potential group that may have done this? >> there had been some threats that had come out about that time that the aryan brotherhood had said they might want to get even with people in law

enforcement. >> reporter: get even, because less than three months before hasse's murder, federal officials announced that 34 alleged aryan brotherhood gang members had been indicted for racketeering. the feds thanked, among others, the kaufman county d.a.'s office for its role in the investigation. >> so, a lot of people were trying to put two and two together with the aryan brotherhood. >> it's one thing if it's one individual who went after mark, it's another thing if it is the aryan brotherhood. >> oh yeah, prosecutors, not just in kaufman, but across the state were terrified that -- hey, if this is the aryan brotherhood we're all targets. >> reporter: and then, seven weeks after hasse's murder, another assault on law enforcement. >> the colorado head of the department of corrections was shot here at his front door -- >> reporter: the man's name was tom clements, the highly-regarded head of colorado's prison system. and like mark hasse, a public servant.

>> with more than 20,000 inmates in colorado's prison system, tom clements may have had a lot of enemies. >> reporter: it was another bold attack, this time inside the front door instead of outside the courthouse. evidence pointed to a former inmate named evan ebel. he was a member of a white supremacist gang in colorado similar to the aryan brotherhood. now, he was on the run from colorado authorities, armed and dangerous. two days after the murder, a sheriff's deputy in texas would find out just how dangerous a violent attack caught on dashboard camera. the deputy stopped this car because the license plate didn't match the vehicle. he had no idea the driver was evan ebel. as you're about to see, ebel had no hesitation about using his gun again. the unsuspecting deputy, shot in the face, would survive. ebel was quickly chased down by law enforcement, and died in an explosive shootout in wise county, texas.

>> searching for clues in wreckage of chase shootout -- >> this is cellphone video of thursday's shootout in wise county. >> reporter: what grabbed the attention of investigators in the mark hasse murder is this -- wise county is just 100 miles from kaufman. could evan ebel have killed another public servant in texas seven weeks earlier? >> the fbi is now investigating this case. they want to see if ebel is connected to mark hasse's murder. >> reporter: two public officials gunned down in two states. someone seemed to be targeting law enforcement at point-blank range. >> reporter: coming up -- as the investigation grows more urgent, sudden concerns about d.a. mike mclelland, and his wife, cynthia. >> i tried mom. and she didn't answer. so i tried mike. and he didn't answer. so i said, okay, i'll go over there. >> reporter: and then, concern becomes alarm.

>> at that point, something is really wrong now. >> reporter: when "dateline" continues. fleas and ticks for a full month. this one little nexgard chew is the #1 vet recommended protection. and it's the only chew, fda approved to prevent infections that cause lyme disease. plus, it's safe for puppies. there's a lot of power in this one little nexgard chew. nexgard. what one little chew can do. ♪ charmin ultra soft! it's softer than ever. charmin ultra soft is twice as absorbent so you can use less. and it's softer than ever... so it's harder to resist. okay, this is getting a little weird. we all go, why not enjoy the go with charmin? i wanted more from my copd medicine that's why i've got the power

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investigators. >> it made people wonder if, perhaps, there could be some connection with the hasse murder. >> reporter: they did tests on suspect evan ebel's weapon. his bullets were identical to those that killed the prison chief, back in colorado. but then the texas task force found out ebel's gun was not the weapon that killed mark hasse. and what's more -- >> ebel was deemed not to have been in kaufman at the time that hasse was killed. >> reporter: so eight weeks in, the hasse case was going nowhere. >> fewer and fewer leads are coming into the investigation. >> reporter: the command post was shut down, leaving just a small group to work fulltime on the case. >> slowly, you know, we kind of trickled back to our daily duties. >> reporter: the passage of time was allowing shannon hebert to finally get her equillibrium back.

>> i just wasn't checking out my windows constantly, or-- worried about when i pull out of my garage, if someone will be waiting there. so you know, i think, you just start letting your guard down again, and life just kinda took over. >> reporter: same thing for hard-nosed d.a., mike mclelland, according to his step- daughter, christina. >> did things just naturally kind of start getting back to normal? >> yeah, i think more of a sense of normal. it was still kind of at the forefront of, "oh, god. we haven't found anything yet. oh, god. we haven't solved this yet." but you know, life moves on. >> reporter: for the mclellands, moving on meant spending time with family. it's something mike enjoyed since marrying cynthia when christina was 10 years-old. >> he would give great big bear hugs and, you know, even when i was older, would pick -- wrap me and pick me up. and you know, i'm like, "oh, my god. i'm 22." >> did you feel lucky that you got mike as a stepdad? >> i do. our personalities are just quite similar. >> you're both straight shooters? >> yes. we're both very -- our -- our filters are quite -- quite off sometimes. >> reporter: mike relied on the support of his wife cynthia, who was always doing what she loved, quilting, entertaining and

cooking. >> and you know, she's the old-school cook who didn't use packages. she bakes everything from scratch. >> was he happy that she was this baker slash cook? >> clearly. clearly, by his physique, he was very -- he enjoyed the food very much. >> what made them a good match? >> you know, it's really funny. she supported him greatly in what he was doing. but he's the, you know, the conservative. and she's very liberal. so i think it was just a lot of balance. i think they balanced each other really nicely. >> reporter: cynthia also wanted her daughter to find love and wasn't shy about playing matchmaker with a guy she thought was a good fit. >> she looked at him and said, "do you believe in arranged marriages," which i -- i had to later apologize for. because you know, that's a weird thing to say. s it's embarrassing! >> it's just weird. >> reporter: at the end of march, easter weekend, the mclellands were looking forward

to a big sunday dinner cynthia was making for friends. the perfect time to relax and not dwell on the tragedy of mark hasse's murder, at least for a little while. >> was there any fear that, "we need to be on high alert?" >> at that point, i don't think so. >> reporter: christina spoke to her mom and step-dad on that friday night. you know, mom was making the and mike was griping at her about what she was doing. trying to put the little peeps on sticks. and she wasn't quite getting it. and she was making a huge mess and, you know, just the normalcy of mike just, you know, "dammit, cynthia. you need to sit down and take a break and," you know, and, "cause you're getting tired. and just give it a minute." and mom, "oh, i'm fine." >> reporter: the next morning, saturday, the sun rose over the mclelland house. it was cynthia's day to prep. >> she had sent me a text about the menu that we were gonna have for easter. >> reporter: leah phillips and her husband, close friends of the mclellands, were excited about joining them for dinner. >> she was making our family all easter baskets. and then she would make clues

and hide the easter baskets. >> wow, that's elaborate. >> right. it was very elaborate. >> reporter: leah, who was supposed to drop off some vegetables for cynthia, texted her. >> and she never answered me back. >> did you think that was odd, that she didn't answer you back? >> the only thing i could think of was maybe she did go into work where she couldn't either answer the phone, or text me back. >> reporter: leah called mike's phone, and the house phone. no response. and she wasn't the only one. christina was also trying to call her mom and stepdad. >> i tried mom. and she didn't answer. so i tried mike. and he didn't answer. >> reporter: by now, it was late afternoon, so leah took things into her own hands. >> so i said, "okay, i'll go on over there." >> reporter: she did go over, and nothing would ever be the same again. >> reporter: coming up -- >> the door opened in slow motion. inside the mclelland house, a heart-stopping discovery. >> i screamed, and then i just -- my knees buckled and i

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>> reporter: on the saturday morning before easter, leah phillips hadn't been able to reach her good friends, cynthia and mike mclelland. leah had some groceries to drop off for cynthia, so she decided to drive over. she thought something was odd when she pulled into the driveway. >> the newspaper was still in the yard and cynthia's car was there. >> so very subtle clues. >> just subtle. but i'm still thinking maybe they went to the movie with someone. >> reporter: leah called her son, cj tomlinson, and told him what she'd seen. >> and i said, "you just stay where you're at. don't go inside that house." >> reporter: it was cj's cop sense kicking in -- he's a dallas police officer. >> the feeling was, something is not right. it's just not right.

>> reporter: a few minutes later, cj drove up, along with his dad. >> we went to the door and cj knocked on the door, and yelled for mike three or four times, and there was no answer. >> they were messing with the key. and they were all standing behind me and i just reached down to see if the door was open. and, yeah, it was unlocked and i will -- i'll never forget how that door opened up. >> the door just -- it "ee-eked" open, just like in slow motion. >> i took a couple steps in and -- and that's when mom hit the ground and started crying. >> and i screamed, "cj, stop. there's shell casings." and then i just -- my knees buckled and i hit the ground and just start crying, because there's not supposed to be shell casings inside somebody's doorway. >> i look down and sure enough, there -- there are two shell casings right inside that front door.

at that point something is really wrong now. something bad happened. so i take a couple more steps inside. and i see cynthia laying there. >> reporter: cynthia mclelland was dead. her body was lying in a pool of blood on the living room floor. cj turned his mom away from the scene, and took her back to the car. meanwhile, cj's dad had gone farther into the house, and found the bullet-riddled body of mike mclelland. >> when your husband and son come back out of the house -- >> there's no blood left in their face. they're white. >> reporter: kaufman district attorney mike mclelland and his wife cynthia had been shot to death. >> you never expect to have to see somebody like that that you knew, that you loved. that -- that was so close. and -- i think that was the most -- and it still is, obviously. it -- it's so difficult. >> reporter: because she hadn't been able to reach her parents,

christina, decided to drive to the house as well. her mom's friend, leah, met her with the news she was dreading. >> i just had the feeling that they were dead. and i said, "both of them?" and she said, "yes." and then it occurred to me that, "oh, my god. this is gonna hit the news." and my grandmother watches the news every day. and somebody needs to stop her before she turns on the tv. >> mike is high profile. >> he is -- he was. i didn't want somebody else to tell her that this had happened. >> reporter: looking at the scene, cj tomlinson's police training told him the killer or killers were long gone. he knew what he had to do. >> there was no reason to go back in that house. we closed the door. we didn't call 911. there was no need for paramedics to go in there. >> reporter: they called the kaufman county sheriff. >> the things that were in that house were very important. and they needed to be preserved until the right people show up.

and they did. they showed up. >> i was at my house and we'd just finished an easter egg hunt with about 30 kids in the backyard. >> reporter: about 8:00 pm, prosectutor toby shook got a call from his partner, bill wirskeye. >> he said, "hey, the mclellands were found murdered. and the sheriff wants us out there." and it -- it scared me to death. when i left the house bill came to pick me up and -- and -- my wife had two guns out. and i said, "unless you know be ready to use them." >> reporter: the prosecutors raced to the scene. >> it was surreal. i mean, the front yard's lit up and it's got the yellow crime scene tape and there's lots of sheriff's officers and texas rangers and fbi there. >> reporter: shook saw sheriff david byrnes standing on the lawn. >> sheriff byrnes is a pretty legendary guy, former texas ranger captain. he was visibly shaken up. and if sheriff byrnes gets shaken up that scared the hell out of me. and all law enforcement out

there was quiet. it was eerily quiet amongst them, because they were dealing with something i don't think any of them have ever seen before. >> aside from the obvious, two people are dead, what was shaking them up so badly? >> i think the big question is who's next? because everybody's assumption that was standing outside that yellow crime scene tape was, "it could've been one of us." >> reporter: cynthia's murder escalated the danger, not just for law enforcement, but now for their families. >> this man had crossed the line and gone into murdering family members. i know my thoughts and prayers were with my wife and children back in dallas. >> reporter: it sure seemed like the hasse and mclelland murders were connected, and everyone was terrified the killings might not be over. >> did you start to think that there was a list? >> oh, sure. there was gonna be another victim if this person wasn't found. saturday night, shannon was

having easter dinner when she was shocked. >> who's there on easter weekend? i won't answer right now. >> but her phone kept ringing. it was another prosecutor from her office. >> i knew then, something is going on and i answered. she proceeded to tell me that they were found. >> their house, shot. >> it must have been the biggest bombshell of your life. >> it is so hard to imagine anyone you know being killed. i was frantic. it was terrifying. >> her colleague told her to watch her back. >> we don't know if there are more attacks tonight. just get home. watch out. >> are you feeling that we're all targets now? >> we all felt that. >> including the people she loved most in the world. >> i think that was what was most scary. it is not just me anymore. i have young kids. my husband. my family. and i mean, i can't keep putting

them at risk. we were all in danger. >> as local deputies began around the clock watch over shannon's house, something kept nagging at her about the mcmcclellanand murders. >> there's no way she podium door to just anyone. it was someone we know or someone who was dressed up as police officer. >> that someone could be dressed in a fake police uniform? >> right. >> reporter: investigators also wondered how the killer could have gotten inside the mclellands' front door. mike, like his entire staff, was still vigilant ever since his chief prosecutor was gunned down. the wary d.a. kept his own guns on a table near the front door, but never got the chance to use them. >> is it just like all bets are off when you hear that now they're going after family members? >> even though you don't condone it, you almost understand someone going after a prosecutor for what they do for a living, but to go after a prosecutor's family, was just a line that we didn't think we'd ever see crossed.

>> coming up, who could pick up law enforcement like this? >> it was straight up, who done it? >> we're hoping that there's a magic clue that will answer the riddle for us. >> when "dateline" continues. e s to australia. mucinex lasts 12 hours, so i'm good. now move- kim nooooo!! mucinex has a patented tablet that lasts 3x longer, for 12 hours.

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the murders were bold. two months later, they were killed before dawn in their home. they knew she had shell casings wolf there be other choose the help catch the killer? >> it was a straight up who done it. we didn't know. >> eric was part of the team entered the home.

>> the front door was not kicked in. the door was unlocked. there's shell casings approximately four foot in. shell casings are .223 caliber. >> reporter: that told them the killer used an ar-15 or m-4 type semi-automatic weapon like this one. >> this started exactly when the door opened. mrs. mclelland and mr. mclelland were retreating and trying to get away from the gunfire. >> reporter: cynthia's body was in the middle of the living room, and she clearly wasn't expecting anyone. >> she's not dressed for company. she's tryin' to get dressed. mr. mclelland's the same way. he's in jogging pants with no shirt on. >> reporter: there were shell casings next to mike's body, indicating the killer had finished him off at close range. >> the suspect was standin' right on top of him, over him, shooting him. >> reporter: to investigators, like lt. jolie stewart of the sheriff's department, it looked like a carefully planned operation, an ambush, just like the hasse murder. >> did the scene speak to you at

all? >> i felt like whoever went in there had a mission. and they did it quickly. and they did it efficiently. and they were out. >> reporter: later, records from the home security company would confirm stewart's observation. the killer entered the house at 6:40 am, and was gone just two minutes later. twenty shots fired in 120 seconds. >> that was a pretty brutal way to go. >> reporter: lt. stewart couldn't help but be affected by the sight of cynthia shot in the head at close range. >> just looking at her there on the scene. she was targeted, you know. i mean, she didn't have a dog in this fight. >> reporter: investigators talked to neighbors. surely someone had heard the shots. assault rifles aren't quiet. >> the weapon used in this murder, you should have been able to hear it outside.

no problem. >> reporter: no one heard or saw anything. by the end of easter weekend, special prosecutor bill wirskye said they had nothing. >> we're just trying to figure out what to do next. and we're hoping against hope there's gonna be a magic clue in that crime scene or in that house that'll answer this riddle for us. >> reporter: they were looking for that clue, and all of a sudden, it drove by. >> reporter: coming up -- a mysterious tip arrives, but, after so many false leads, is this one legit? >> would anyone other than the killer have known that? >> no. >> reporter: when "dateline" continues. ♪ free? free... free.

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>> reporter: what should have been a slow easter newsday in dallas, now had a lead story that didn't involve chocolate bunnies or egg hunts. >> we're following some breaking news right now in kaufman county, where county district attorney mike mclelland and his

wife cynthia have been found shot to death. >> reporter: the news touched off a firestorm of public concern. tips started flooding into the re-opened kaufman county sheriff's command post. some tips still cited the aryan brotherhood of texas. >> with the added media attention after the mclellands were murdered, we got hundreds of tips a day. >> it was like drinking out of a fire hose during this whole thing. >> reporter: lt. jolie stewart of the sheriff's department was right in the middle of it. hundreds of investigators from multiple agencies had swooped in. >> this was all hands on deck. >> uh-huh. >> this became the number one case in the bureau at that time. >> reporter: fbi special agents michael hillman and laurie gibbs who has since retired, were coordinating teams from the task force, each team looking into different aspects of the case. >> you have to look at everything. >> so you decided to just divvy it up everyone could focus on their individual tasks? >> exactly. >> right, and some of these teams had 25, 30 people on them.

and there was a team that looked at all of the victims and what they may have in common. >> reporter: they believed the killing of d.a. mike mclelland was linked with the shooting of prosecutor mark hasse back in january. but it was all one big collective hunch, until a tip came through that would confirm the connection. >> through the crime stoppers web-based tip line, we get a tip that claims credit for the mark hasse murders. >> reporter: the electronic message came in easter sunday night. it began, "do we have your full attention now?" >> "we" suggests more than one person. did you think maybe it's a group? >> in my thought i thought is it -- how big is this group? what is this group? is this some sort of anti-government militia group? is this white supremist? i -- i had no idea what we were dealing with. >> reporter: law enforcement wrote back, "you have our attention." >> and we wanted him to tell us what he wanted. >> reporter: while they waited anxiously for an answer,

computer experts tried to trace the tip back to the source. no luck. that's because the system is set up to protect the anonymity of all tipsters. when a message comes in, the sender is identified only by a unique number. after 12 hours of nail-biting, there was finally a response that told investigators this person was the real deal. mark hasse was killed with 38 caliber ammunition fired from a 357, five- shot revolver. >> would anyone other than the killer have known that? >> no. this person knew way more than anybody would have. >> the killer also wrote, "your act of good faith will result in no other attacks this week." in return for that pledge, the killer made a demand. >> they wanted one of the judges in kaufman county to step down by the end of the week. or the killings would resume. so, the fact that this tip came in and named these specific judges in kaufman told us it was somebody local. >> reporter: that all but ruled out the aryan brotherhood, drug cartels and those old cases from dallas. the killer's message ended this

way, "we are not unreasonable, but we will not be stopped." >> it's almost sounding like a game now. >> i think in his mind it was a big chess game. i think it was just for fun, to see if he could really exert complete and total control over the criminal justice system in kaufman county. >> reporter: by monday morning the story was topping the national news. perhaps that's exactly what the killer wanted. >> nbc's gabe gutierrez is in kaufman, texas for us this morning. gabe, good morning to you. >> savannah, good morning. there will be stepped up security here at the county courthouse today. the district attorney's office will be closed to the public. this entire community is on high alert. >> reporter: that morning, when shannon hebert came to her office, she had an armed escort. >> there's no leader at your office anymore. >> there's nothing. no one. >> when you come into work, how do you go forward? >> we had to move forward. we couldn't let them win. we couldn't.

and we had to fight, and -- for the honor of mike and mark. >> reporter: everyone in the office was on edge. >> my husband. i mean, he stayed up all night with a gun in his hand. >> i know that i start carrying a gun. sleep with a gun under my pillow. >> reporter: even shannon, who wouldn't carry a gun before, now slept with protection nearby. >> we had a big old shotgun sitting on our dresser, just way -- ready to go, in case. >> reporter: the killer's threat to unleash more violence in kaufman county kept the task force working around the clock. a special team scoured the surveillance video collected near the mcclelland crime scene, hoping for a new lead. >> so many people now have surveillance cameras on their house. so, we're trained to go in and collect that sort of evidence. >> reporter: and, finally, the video team's painstaking search seemed to pay off. they found images of a car that didn't belong, a white ford crown victoria, cruising near the mclelland home about the time of the murders. no one in the neighborhood owned a car like that. but the crown vic model is popular with law enforcement.

so the fbi jumped on that angle. >> was there ever a thought that maybe this is one of our own? maybe this is a police officer doing this? >> that was not out of the realm of possibility. >> reporter: coming up -- investigators recheck the cases handled by mark hasse, this time to see which ones mike mcclelland also worked on. and -- >> there was only one common denominator for those two prosecutors. >> which was? >> reporter: when dateline continues. confidence, reassurance you're doing what's right, to protect your dog from fleas and ticks for ll month. this one little nexgard chew is the #1 vet recommended protection. and it's the only chew, fda approved to prevent infections that cause lyme disease. plus, it's safe for puppies. there's a lot of power in this one little nexgard chew. nexgard. what one little chew can do.

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hello. a second person has died from coronavirus in the u.s. this at the same washington state facility where a man was reported dead yesterday. overnight, new york city reports the first confirmed case of the virus in manhattan. the civil rights icon and congressman john lewis was among those commemorating bloody sunday in selma, alabama, on

sunday. he was joined by a number of democratic candidates. he was badly beaten in that march 55 years ago. now back to "dateline." >> reporter: six days after the murders of mike and cynthia mclelland, hundreds of mourners packed this church for their funeral. the flag-draped casket contained mike's body and cynthia's ashes, together for eternity. their extended family, united in grief, bid them an emotional farewell. >> i carry a lot of things from them with me. they taught me very well. they helped a lot of people before they left this world. they really did. they made a large impact on a lot of people. >> reporter: a beefed-up multi-agency task force vowed to catch whoever killed the mclellands and mark hasse.

investigators had seen that ford crown victoria on video roaming near the mclelland home and thought it might be a police car. the terrible possibility it might be one of their own had to be ruled in or out immediately. >> we checked with every law enforcement agency in the area and identified where every police car was in the area. and none of them were even close to where this image was captured. >> reporter: next, they looked for anyone, who for any reason, had issues or disputes involving both prosecutors. >> there didn't seem to be anybody in that group of people that were upset enough that they would want to commit homicide. >> reporter: but there was one defendant involved in a felony they couldn't ignore. >> there was only one common denominator for those two prosecutors. >> which was? >> that was eric williams. >> reporter: eric williams? who was eric williams? he was a former deputy sheriff

and longtime attorney with an office right across the street from the courthouse. in 2010, he was elected by the people of kaufman to be justice of the peace. shannon hebert worked with him said he had a sharp legal mind. in fact, he was a member of mensa, the organization for people with super-high iqs. >> he was a great judge. i liked having him in there. i thought he was very fair. >> i mean, everyone respected him. >> reporter: williams, married for 15 years with no kids of his own, was a strong advocate for children and specialized in child abuse cases. lt. jolie stewart often worked with him on those cases. >> how do you think he was perceived amongst his fellow colleagues, other attorneys? >> i think that he had a lot of respect with his peers. he was kind of the go-to guy for family law. >> i know he had a love for children.

>> reporter: tera williams-bellemare knows that better than anyone. she's eric's sister. >> he was a good uncle to my kids. never missed their birthdays. i never had to remind him. >> reporter: she says, growing up, her big bother was her inspiration. he made eagle scout, went to college, law school and became a successful attorney. he also served as a captain in the texas state guard. >> he was driven, he was ambitious. he wanted to make us feel proud of him. >> reporter: so tera and the legal community were stunned in 2012 when her brother, the newly-elected justice of the peace got into trouble with the law. williams was accused of stealing three computer monitors for his personal use from the county i.t. department. here's surveillance video -- showing him carrying boxes of computer equipment. >> it just seems odd that someone like that would bother to steal a few computer monitors. >> exactly. it was just kind of shocking

that someone would go and do that. >> reporter: williams found himself on the wrong side of this police interrogation. >> okay, judge, before we get started, i'm gonna read the miranda warning. you're an attorney, you're a judge, so you know as well as i do. >> i know you gotta read. i understand. >> reporter: williams tried to explain he took the monitors because he claimed he needed new equipment for his office but never got it. >> that's been an ongoing kind of thing, where i'd tell the i.t. people that i need to keep improving things. >> i understand. but you hadn't put any kind of written request in, nothing like that's been documented at all? >> no. >> reporter: mark hasse and mike mclelland knew eric williams as a colleague in kaufman's small legal community. as boss of the da's office, mike rarely tried cases but because williams was an elected public official he made an exception and teamed up with mark to prosecute the case. christina says her stepdad believed williams had violated the public trust. >> i think it did offend mike, on a basic level. these people elected you.

you're supposed to be doing good things for the community, not stealing from it. >> reporter: a jury found williams guilty of theft. he got probation, but lost his job and license to practice law. and now, a year later, both men who prosecuted him were dead, and williams was under suspicion. >> did you bear either of those men any kind of grudge? >> no. absolutely not. >> reporter: the media got wind of the interest in williams. and, just days after the mclelland murders, he was interviewed by nbc affiliate kprc. he strangely swept in on his segway. >> has anyone connected with this investigation suggested to you that you're a person of interest in the investigation? >> no. >> reporter: after the denial, his sympathies. >> my heart-felt condolences go out to both the mclelland family and the hasse family because they were in public office doing the right thing and for some reason, that we're not aware of, they've paid the ultimate price for that.

>> reporter: williams was known to be a bit of an odd duck, but a murder suspect? >> it seems so farfetched that a justice of the peace, a man who had served his county not only as an attorney, a judge, but also as a -- as a deputy sheriff, would then suddenly turn into this serial killer. >> uh-huh. yeah, no -- no one wants to think a lawyer would do that, a person who was a public servant would do that. >> reporter: in fact, he was among the many people investigators had already looked at after the hasse murder. >> what was his alibi at the time? >> he said he had been at home either caring for his wife or his in-laws down the street. >> he also had his arm in a sling when law enforcement came to talk to him and his excuse was he had frozen shoulder, and wasn't able to use his right arm. >> reporter: he even took a gunshot residue test at his house and passed. and after the mclelland murders, investigators checked whether he owned a ford crown victoria, the car captured on video lurking near the mclelland murder scene.

records showed he did not. the case was still stalled. but soon, the task force would get one of those lucky breaks they'd always hoped for. it came out of the blue and gave the investigation some much-needed juice. coming up -- >> i told my wife to know where the kids were and keep the doors locked. a stranger calls with a stunning revelation. >> i could tell when i listened to his voice, "this is it. this is the real thing." when "dateline" continues. woman: the deadly corona virus

officially hitting the us. man: the markets are plunging for a second straight day. vo: health experts warn the us is underprepared. managing a crisis is what mike bloomberg does. in the aftermath of 9-11, he steadied and rebuilt america's largest city. oversaw emergency response to natural disasters. upgraded hospital preparedness to manage health crises. and he's funding cutting edge research to contain epidemics. tested. ready. mike: i'm mike bloomberg and i approve this message. >> "i've cooperated with law enforcement and certainly wish them the best in bringing justice for this just incredibly egregious act." >> reporter: eric williams was making the tv interview rounds.

but he hadn't sat down for a formal interview with investigators. because of his connection to both mark hasse and mike mclelland, investigators had to take a serious look at him. >> on the surface it may seem implausible, because he's a lawyer and a judge and successful. the more we learned about him, the more viable in our minds he became as a suspect. >> reporter: just the year before, williams had been prosecuted for theft by hasse and mclelland. >> you must be chomping at the bit to talk to eric williams. >> obviously, we wanted to talk to him. the problem with that was he was still represented by lawyers. >> reporter: lawyers who kept williams from talking. but then, two weeks after the mclellands were killed in their home, the special prosecutors got a big opening they hadn't seen coming. >> we get an e-mail back from the lawyers basically saying, "we do -- no longer represent eric williams." >> reporter: they figured this was their one window to talk to him, and they knew they had get it right the first time, before he lawyered up again. so fbi profilers came up with a

strategy, send over a top-level texas ranger so williams would be more likely to let him in. >> was the idea that that would fit with his ego? >> he would view a major with the texas rangers as someone equal on his intellect that perhaps he would talk to. if you sent someone of lower rank, then he would just dismiss them. >> reporter: the ranger, and a local cop familiar to williams, went to his house carrying a hidden tape recorder. >> did it work? >> it worked great. >> reporter: williams let them in, without a search warrant. the subject quickly got around to guns. williams said he'd been forced to sell his weapons to raise money since he could no longer practice law. >> i been in your house. i know you got lots of guns. >> yeah. how do you think i've been living? >> selling guns? >> yeah, for two years. >> you don't have any more? you got rid of all of them?

>> i have one gun that i'm trying to sell, and it's just hard as [ bleep ] to sell. >> he said, "i don't have any guns, except one gun." and so, he let them look around. and -- and they began finding gun parts. >> reporter: gun parts. some very specific gun parts that appeared to match the type of automatic weapon used in the mclelland killings. and at the same time, the fbi discovered williams had done computer searches on hasse and mclelland before the murders. >> specifically told them that he had not ever searched the two victims before the murders. >> now you've got him lying? >> yeah. >> reporter: that lie and those gun parts were enough to get a warrant for a more thorough search of his house. investigators, including a crack fbi evidence team, were back the next day. they went room to room, then to the garage. and, bingo! >> in a filing cabinet in the garage there was a manual for a ford crown vic. and there was also a title to a crown vic.

>> reporter: the task force, of course, had been looking for a crown victoria. this one was registered under a false name. >> that must have been a real big moment finding that registration. >> that was huge. >> reporter: outside, special prosecutor wirskye was on hand to give legal advice. >> one of the fbi computer techs came out and said, "mr. wirskye, i don't mean to alarm you, but eric williams has been searching you and mr. shook on his computer." >> what's the first thing you did when you heard that he had been searching you? >> get on the phone with my wife and tell her to make sure she knew where the kids were and to get inside and keep the doors locked and don't answer the door for anyone up to and including a police officer. >> what did she say? >> i could hear the fear in her voice, and i knew right then we had to put him in jail for something. it became very personal and a matter of life and death for us. >> reporter: back inside, searchers found something interesting, a scrap of paper with two handwritten numbers. >> so they collected it because it was near the computer and they thought it might be important.

>> reporter: and it was! a sheriff's deputy recognized the user id for the county crime-stoppers' anonymous tipline. the first number corresponded to a tip from early in the hasse case: the tipster claimed to have overheard two men in a bar saying they'd killed mark hasse. that meant the tip came from william's computer. a follow-up computer search also revealed williams had searched several how-to websites. >> one of the websites was how to throw the police off an investigation by sending in fake tips. >> reporter: the second number on that scrap paper was even more important, because it turned out to be the real thing. it matched back to that computer message that gave details about the hasse murder weapon and also threatened more killings. >> so, we knew right then that that tip that had come into the command post was sent by eric williams. and we knew right then we were gonna be able to put eric williams in jail. >> reporter: he was arrested, not for murder, but for making a terrorist threat about killing a judge.

>> we just didn't know if we at that moment had enough evidence to convict him. >> reporter: they just had to figure out where the evidence might be. >> did you think that eric williams had a hiding place? >> we began to suspect pretty early on if it's eric williams and we know what cars were used there may be a storage unit or some secret storage place that he may have access to that we haven't found. >> reporter: at least now, 10 weeks after hasse's murder, the investigation was finally on a roll. >> we go home that night to get a good night's sleep and i actually wanted for the first time in weeks to see my son play a little league game. >> reporter: but the next morning, his parenting plans were dashed by work again. his phone rang. it was a friend of eric williams, who'd heard about his arrest. >> and said, "mr. wirskye, i have something to tell you about eric williams. i think i may have rented him a storage unit." >> we'd been looking for a storage unit and i could tell

when i listened to his voice, "this is it. this is the real thing." >> little league was out for the day? >> unfortunately, it was. little league was out. my son went three for three. >> but you were headed to a storage unit. >> this is too important. so, i got on the phone with the texas rangers. and i said, this is it. i think we've found it." >> reporter: coming up... found what, exactly? even seasoned investigators would be blown away. >> this is one of those moments that i'll never forget because it was just "wow." >> reporter: when dateline continues. frustrated that clean clothes you want to wear always seem to need an iron? next time try bounce wrinkle guard dryer sheets. just toss it in the dryer to bounce out wrinkles.

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>> reporter: the hot spot in the investigation was now a run-of-the-mill storage unit -- number 18 to be precise -- in seagoville, texas. just 14 miles from the mclelland house. eric kasper of the texas rangers was part of the task force caravan racing to unit 18. >> everybody is running and gunning. you know, everybody wants to be there. >> so we're all just filled with expectations. we're making bets, "okay, the white crown vic's gonna be there."

"no, it's not." "we're gonna find the murder weapon." >> reporter: ranger kasper did the honors, lifting the heavy, steel door. >> this is one of those moments that i'll never forget because it was just wow. >> reporter: what did you see? >> we saw the white crown vic, the car that we'd been looking for for all those days and all those man hours, and there it was. and we knew finally we had eric williams. >> reporter: but there was so much more. police uniforms and bullet-proof vests, more than a half-dozen police badges, thousands of rounds of ammo and enough guns to supply a small army. >> he's got six or seven weapons of the right caliber that could've been the mclelland murder weapon. we have five or six weapons of the right caliber that could've been the hasse murder weapon. >> reporter: did you think that one of those guns had to be the murder weapon? >> i felt like our chances were pretty good. because there were just so many in there. >> reporter: the guns and ammo were sent off to the lab for testing. inside this treasure trove of bad intentions, there were also pickle jars filled with liquid, later identified as homemade napalm. >> it was just unbelievable. it was like a tactical

operator's closet. >> reporter: but they'd soon be dealt a serious blow. the lab results came back on all those weapons. nothing matched. the murder weapons were still missing. that's got to be extremely frustrating when you feel like, well, one of these guns i'm sure has got to be the murder weapon. >> oh yeah, deflating. we were positive one of those was going to be the murder weapon. >> reporter: even without the guns, the prosecutors believed there was enough evidence to finally go forward. on april 18th, 2013, 10 weeks after mark hasse was gunned down and three weeks since the mclelland's were killed, eric williams was charged with three counts of capital murder. prosecutors said the motive was revenge. >> one thing i found out about

eric williams, the first big thing that went wrong in his life, this is how he was going to react with rage and homicidal violence. >> reporter: it all seemed so senseless to the mclelland's daughter, christina. this all started over three computer monitors. and now we're talking about three murders. >> yeah. i mean, you know, normal people don't do that. >> god bless the united states and the great state of texas. >> reporter: eric williams went on trial for murder in december. >> be seated please, ladies and gentlemen. the court calls state of texas versus eric williams. >> reporter: williams wasn't on trial for the murder of mark hasse or mike mclelland. in a surprise tactic, this trial was only for the murder of cynthia mclelland. why not just try the murders at the same time? >> what if something went wrong in the first trial? we wanted to have the ability to be able to try him twice and make sure he got justice. >> reporter: christina sat in court and had to relive the deaths of her parents. >> what gave you the strength to go to court every day? what gave you the strength to go to court every day?

>> they showed up every day for the three people who gave their lives for something good. they stood up. and they did what they were supposed to. and they died for it. >> this is my chance to tell you story of the murders of mike and cynthia mclelland. >> reporter: prosecutor bill wirskeye thought if he could prove eric williams had killed cynthia, that would obviously show he killed mike. >> you'll hear the story of a massive law enforcement investigation -- state, local federal agencies working together to build an air tight case. >> reporter: one of the first witnesses called -- cj tomlinson, dallas police officer and friend of the mclellands. cj told the jury how he and his parents found the mclellands. >> i took a couple more steps inside the residence, i was hollering for mike. "mike, mike!" >> reporter: for three days, prosecutors brought a blizzard of witnesses. they told the jury williams had been linked to that tip that came in after the mclelland murders. >> he sent an email into law enforcement claiming credit for the murders, thinking law enforcement would never figure

it out. but he was wrong. >> reporter: investigators didn't have the murder weapon, but they had something else, a bullet they found inside a bag taken from williams' storage unit. >> you know this is what you and your team recovered. >> yes. >> reporter: a ballistics examiner compared that single unfired bullet to the shell casings found at the murder scene and came up with a match. >> that live round was ejected from the same weapon that killed the mclellands. so, that was a big moment for us. >> reporter: and prosecutors thought this security video outside the storage unit nailed the case down. they said it traced the movements of eric williams and the crown vic on the morning of the murders. >> approximately 6:00 a.m. real time. >> reporter: that's when williams -- in his black suv--- pulled up to the entrance of the storage unit, according to the prosecution. at 6:12 a.m. the white crown victoria pulled out. by 6:42 investigators knew the mclelland's were dead or dying on the floor, based on the motion detectors in the home security system. at 7:00, here's that white crown

vic coming back through the entrance. and 17 minutes later, that black suv pulled out. >> he committed this crime. his acts alone, and his acts alone, condemn him to be found guilty of capital murder. >> reporter: the prosecutors said they had a lot of circumstantial evidence, including the crown vic and that matching bullet. but the defense was about to tell the jury what the prosecution didn't have. >> ladies and gentlemen of the jury, eric williams did not commit these murders. >> reporter: defense lawyer, mathew seymour laid into one of the state's star witnesses, that ballistics expert. he reminded the jury, investigators never found the murder weapon.

>> you didn't actually have access to that firearm? >> correct. >> reporter: he tried to poke holes in the prosecution's matching bullet theory. >> someone of different experience could come along and say they're not a match. is that true? >> yes, potentially that is true. >> if i could break the chain from the live round recovered from the storage unit and the mcclelland shooting scene, i might stand a chance. >> reporter: the defense didn't see the need to call any witnesses. >> our position was the state had not fulfilled their obligation to prove the elements of the indictment. it was just that simple. there is no known murder weapon in this case. there's no one who can place eric williams in that scene at the mclelland home. no one. >> reporter: finally, this case that had rocked the justice system was about to be decided by the jurors. they needed only 90 minutes to reach a verdict. >> we the jury unanimously find the defendant, eric lyle williams, guilty of capital murder as charged in the indictment.

>> reporter: guilty of capital murder in the death of cynthia mclelland. you heard the word, guilty. >> it's a gift. it was a gift for us. it's probably a gift for everybody else because i don't believe that this would've stopped at the end of these killings. >> reporter: there's a sad postscript to this case that raises a painful question. could williams have been stopped after the hasse murder and before the mclelland's? did they have to die? in a haunting irony, mike mclelland always thought williams was likely the killer. >> he certainly suspected it was eric williams after mark hasse was shot. and he made no secret of what his opinion was. and i had numerous conversations where he said, "bill, it's eric williams. >> reporter: williams was one of a handful of possible suspects, early on in the hasse case, but there was no evidence on him. and even with his conviction for theft, he'd had a good reputation. >> of course eric's name came up in the discussions. but if you can't prove it, then it doesn't matter. it doesn't matter what you think, if you can't prove it. >> reporter: and now this former justice of the peace was a

convicted murderer. how? why? was he living a double life? >> i think he was. most people were fooled by his exterior. he looked so normal. he looked so average. he had the trappings of success, being a lawyer and a judge. but behind that mask was a homicidal psychopath. >> reporter: just angry at the world? >> yeah, i think he had a very dark, cold heart. >> reporter: but this case was far from over. prosecutors had won, but they were saving their best witness for last. investigators always suspected eric williams did not act alone. and he didn't. you're about to hear from his accomplice, someone who will take you inside the mind of a murderer. >> you just can't make this stuff up. >> a plot more chilling than anyone realized. >> as you were driving away from

the scene of the murder -- what his mood? >> happy. >> what was your mood like? >> happy. >> i think that lets you know what kind of darkness was going on inside their hearts. >> when "dateline" continues. we choose to go to the moon in this decade

and do the other things, not because they are easy, but because they are hard. president kennedy knew settling for half-measures wasn't good enough. so when candidates say we can't guarantee health care for all, make college affordable for all, combat climate change, or create a world at peace, remember that america is best when we strive to do big things, even when it's hard. i'm bernie sanders and i approve this message.

we the jury find the defendant -- >> they won a guilty verdict against eric williams. but prosecutors didn't have time celebrate. the jury would now decide whether he should get death penalty in a rare legal move, prosecutors had saved some blockbuster evidence and a star witness for just this moment. as investigators figured all along, williams hadn't acted alone. he had an accomplice. it was this woman. his wife. kim. they'd been married for 15 years.

but now she was about to testify against her husband. >> it was a cold day. there was excitement in the air. >> witnesses to the hasse murder, you remember, said the shooter jumped into the passenger side of the getaway car. so police always suspected williams had help. soon after he was arrested, kim williams was brought in for questioning. >> investigators spent hours talking on her. >> the prosecutor was watching the interview. >> she was just not going to give up any information. she talked about her husband and what a great guy and he was how he wouldn't hurt anyone. >> then an fbi interrogator growing impatient got tougher. >> he raised his voice with her and was telling her that she knew those people had been killed. >> then she broke. and what she told them was startling. she said not only did she know something about the murders, she helped her husband carry them

out. now during the penalty phase, prosecutors planned to use her testimony to make sure the jury would give him a death sentence. >> she led to us a lot of evidence. i think it was important for the jury to see and have all their questions answered. >> he came up with a plan to dress like law enforcement. >> they were a husband and wife murder team. and they went thank you dress rehearse tal night before the mcclellan had murders. >> describe for the members of the jury what he was modeling for you? >> he was in the army. or s.w.a.t. he had a bullet-proof vest that had sheriff on the front. that more than likely mrs. had mcclelland would answer the door and he would introduce himself as policeman. >> the next morning, she said, she acted as lookout in the crown vic as her husband went inside to murder them. >> was there a plan for what you

said supposed to do? >> yes. he told no honk the horn. >> if these had been revenge kills, why did cynthia have to die? >> because she would be there as a witness and he described it as collateral damage. >> and prosecutors wanted the jury to know how callous eric and kim wrims after killing two people in cold blood. >> we had steaks on the grill. eric cooked those. >> at your parents' house? >> at my parents' house. >> you were celebrating with steak? >> that's correct. >> the prosecutors couldn't tell jurors about the cynthia mcclelland trial but now they could use this to cement it. >> kim williams said that morning outside the courthouse she drove the getaway car. >> as you're driving away from

the scene, what was your mood like? >> happy. >> i so believed in eric and everything he told me. his anger was my anger. he was mad at mr. mcclelland. he thought they were trying set him up. >> what did that tell but this incredibly bizarre relationship? >> i think it proved beyond any doubt that eric williams was a psychopath and this was a horribly toxic screwed up marriage. it i think it lets you know what kind of darkness was going on in their hearts. >> kim williams said, she remembers watching eric toss a black bag into the lake. >> did you know what was in the bag? >> i knew it was guns. >> it was 12 months of searching before divers found bag.

the fbi agent lauri gibbs was there. >> i open it up and there are two guns. this was it. >> inside the bag were two revolvers. forensics will show it. and that bag wasn't a bag at all. it was a grim reaper halloween mask. kim williams said her husband wore to it conceal himself. >> you can imagine the terror that was going through mike hasse. >> she told jurors her husband had more mayhem in mind. he wanted to came judge in a special way with a special weapon. >> with a cross bow. >> that's correct. >> she said he also brewed up a concoction just for the judge. you may remember there was home made napalm in pickle cars.

>> what was it for? >> i guess to drive in and gefgs to [ bleep ] a hole in his stomach. >> it is one thing to say that eric williams did it bust his wife was along for the ride in. >> you can't make it up. these people are living every day together and talking about murdering people. >> now christina in her vmi impact statement would finally get her chance to vent her feelings as she turned to her parents' killer. >> pretty much the only thing i have to say is [ bleep ] eric williams. >> that was the only thing i could think of to say to him. >> did it feel good in. >> it did feel good. a nice sock in the face probably would have felt a lot better. >> the defense allowed many defense witnesses. from his scout master to his

high school friends. but the jury wasn't swayed. he was sentenced to die by lethal injection. given the death penalty decision, prosecutors decided not to try him for the murders of mike hasse or mike mcclelland. williams pleaded not guilty to both. his friend and federal trial attorney believes whims still be dangerous even on death row. >> eric williams is a mast matter nip la matter, a master manipulator and a dangerous killer. i think he's a threat to the prison guards and anybody else in prison. >> you're making him sound like hannibal lechter. >> has the man who killed three people this cold blood because they prosecuted him for stealing computer monitors. >> kim williams pleaded guilty to the murder of cynthia.

for her cooperation, the other charges were disposed of. she was sentenced to 40 years in prison avoiding the death penalty. >> i'll never forget cynthia or mark. i'll never be over this. i don't think any of us will be, ever. >> but as tragic as all this was, believe it or not, something good came out of it. during the long ordeal, christina and that cop from dallas, c.j. tomlinson, fell in love. their families have been great friends for a long time of the cynthia had always tried to play match maker. >> cynthia pretty much told me that would happen and she was right. she got me. >> i can only imagine how happy your mom would be if she's looking down, that you two are together. >> i can't even imagine. she would be just doing some sort of weird dance that i told

you so. i'm sure she's thrilled. we got married on her birthday. that would have made her ecstatic. >> i'm craig melvin. >> i'm natalie morales. >> and this is "dateline." she is and will always be my sister. i don't know what happened to her. i don't get to say good-bye. it's so awful. it makes your whole world fall apart. >> if you took her, please, just let her come home. >> her name is heather elvis. it was just nationwide when she vanished. >> she had a new job. she was going out of state. >> it was all so overwhelmingly horrible. >> she's missing. where is she at? >> police worked the clues. her car abandoned. >> i was scared to death.