the local press. >> for me, it's been one of the greatest things in my life. yeah, after all that happened, it was like a healing thing. >> she was like trying to retake her life, not sitting on her bed to cry or stuff like that. >> she helped us. >> she helped you to get through it? im happy being alive, happy being with my family. happy to get a second chance >> hello.

i'm andrea canning. and it sees "dateline". >> i just knew something horrible happened. >> she was a small town girl with big dreams. and they were all coming through in vegas. a career at a casino, and a fiancée -- then, she vanished. >> i remember going to church every day and saying -- >> days later, police did. murdered, blood on her collar, a struggle at her house, and clues from a camisole. what had happened? >> we can't arrest until it's solved. >> her friends will not quit. her parents will not stop. >> i am a pain. and i am a nuisance. but i am a mother. >> can "dateline"'s own team of investigators help? >> nothing is missing from this house. ♪ ♪ ♪ >> hello, and welcome to "dateline" --

it's a puzzle police have struggled to soften more than a decade. what happened to a small town girl who had moved to the big city of las vegas? it was there that theresa insana found a new career and a new life, but then suddenly, she vanished. within days, police would find her body. but finding who killed her, that would be a tough for mystery to crack. here's josh mankiewicz with "lost in sin city". >> las vegas -- every year, these bright lights draw millions. some come looking for the promise of an easy fortune, or for those secrets that supposedly never leave here. and some people come to get lost. if you want to disappear in america, the shadows thrown by those bright lights can hide you. and then there are those who don't want to disappear here. but they do anyway. people like theresa insana.

here one day, and gone the next. >> she was going to make the big time. >> theresa's parents, joe and anne-marie. you guys ever worry about this girl, so far from home? >> me and my sister were very worried about her. >> sure i was worried but i also knew, she's going to do good things. >> doing good things. it was a lesson theresa insana had learned well. as the second of three children in a deeply religious -- family in niagara falls, new york. and from those earliest days of childhood, theresa's best friend was always her doting father. their love was deliciously obvious, spelled out in whipped cream and icing on the extravagant birthday cakes he made for her nearly every year of her life. >> she used to love it. she was a person -- >> you were her friend. >> i was her friend. >> but i was the disciplinarian. not that she was bad.

>> so, she was the disciplinarian. and you were, what? her coconspirator? >> no. >> i was her unable ok. put it that way. [laughter] >> the neighbor fed teresa's love of beauty and fashion, even daddy's little girl, everything that she could want and that he could afford, and more. >> she loved shopping. and i think probably spent a lot of money buying clothes. >> theresa's friends from childhood -- jennifer and grace carducci. -- had the nicest close clothes. and she always looked great theresa but many of those close yourself, working several jobs as a teen. . and beauty and fashion were both small facets of a much larger and meaningful life. >> she was friendly, loving, kind, incredibly smart. >> an a student, she studied psychology in college. but she was also an excellent dancer. and, coupled with her size, she

was barely five feet tall. that skill made her perfect for another of her passions >> we tried out for the cheerleading team together. and theresa those are bad that she made the team and i didn't, she told me she was not going to partake in the team. >> she was a loyal friend. >> yes, she was. >> volunteering to give up something like that. >> yes. she wasn't going to be a cheerleader, because i couldn't be one. >> so, very loyal -- and a postgraduate life of leisure. >> she was home. and she was living with me. but she was going out at night, coming home relate, sleeping until noon. i say, honey, that's not going to happen. you are going to do something. >> so, theresa did, she packed her bags and headed for las vegas. and along with her went melissa, who had grown up next door to the insana family, and remained the best of friends with theresa. >> we both fell in love with it

as soon as we got there. so, we immediately started on the job hunt when we got there. >> within days, theresa had a job in the electric city. not dancing on the chorus line, but working in sales at the -- melissa soon found work at harrods. the two girls from niagara falls got their own apartment. teresa's parents came to visit. >> did she like las vegas? >> she loved. it >> she loved. it there was excitement. we said, wow. >> i will never forget. because theresa was so -- so theresa. and here she was, a -- in her hair, and our starbucks coffee, and she's running down the hallways at the rio. and i say, oh my god. she was so happy. >> theresa's career at the rio was often --

up and running. soon, she met a guy. his name was jeff. -- they bought a dog. they moved into this house together and got engaged. within, he broke it off, just before the wedding. >> theresa was crushed but had moved on, reuniting with her best friends in the summer of 2004, standing up for her friend grace at her wedding. >> we just really we're so happy to be all together. it was a good day >> but a couple of months after, by the fall of 2004, vegas seemed to have lost some of its luster. theresa we're thinking hard about moving back home to niagara falls, and maybe going to grad school. then, the rio offered theresa a bigger job with better pay. >> it absolutely changed the course of her life. i was really, really upset. because i wanted her to come back home. and i thought it was going to

be the best thing for her. >> and going home might have been. staying in vegas, clearly, it was not. because a month after her promotion, on october 27th, 2004, theresa insana failed to report for work at the rio. she was gone for a day. and then for another. so, coworkers, including her childhood friend melissa, went over to her house. inside, no theresa. just her dog. and her keys. her cell phone, her purse and our car. and on the car's bumper, an unmistakable spot of blood >> i think at that point was when i became panic stricken and was like, something was wrong. something is definitely wrong. >> where was theresa? what had happened? and was she still alive? >> coming up -- the investigation begins. police find more blood in the bathroom. >> not theresa insana >> not theresa insana -- >> when dateline continues -- but this is my story. ( ♪♪ )

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>> in a quiet suburb, less than ten miles from the las vegas strip, concern and confusion suddenly ruled. for two days, 26-year-old theresa insana had not shown up at her job as a sales executive at the rio. back home in niagara falls, new york, her father, with whom theresa spoke nearly every day

hadn't been able to reach her >> i just called and get the message machine. you know? >> she didn't call you back? >> didn't call me back -- didn't call me back. and i say, calmly back, what's happening? >> -- finally going to theresa's house to check on her, and found teresa's dog, cell phone, purse and car. and that frightening spot of blood on the bumper of theresa's car. you've known her all her life. and you show up and she's gone, but all her stuff is still there. >> i think at that point i was in complete shock. where was she? >> las vegas metro police responded, and patrol quickly made a call that reached vegas homicide. a squad that included detective marty wildmen, and detective sergeant mike mcgrath was soon on the scene. >> we looked at the blood smear on the rear bumper of the car. and then we said, everybody out. we are taking this.

and we started going through the house -- methodically. processing it as a homicide, basically. >> it looked to detectives as if theresa had been attacked, and the -- founder of the house supported that. on the stairs, a footprint, too large to be theresa's. and this -- >> we saw a small little brass or a metal ring. >> -- in a half bath, detectives found a towel rack missing from the wall, and two more spots of blood, one near the base board, another on the mirror. >> analysis of those two blood droplets from the same person? >> same person. full male profile >> so, not theresa insana? >> not theresa insana. >> then there was that blood on the bumper of theresa's car. that would later turn out to be theresa's blood, not in assailants. detectives prepared themselves for what might be in the cars trunk. but when it was open, they found only a bit more blood and

mud. then, inside the car, police found the driver's seat in an unusual position. >> the seat was pushed all the way to the back. >> and she was barely five feet tall. >> she's a very small woman. >> based on this evidence, a theory was beginning to take shape, a theory that involved an attacker entering the home, possibly in through the -- a struggle that then spilled into that half bathroom, where a towel rack was torn from the wall, and where theresa's attacker lost blood. but no matter what exactly had happened in the bathroom, detectives believed the struggle had ended with theresa's murder. then, the loading of theresa's body into the trunk of her own car, the bodies disposal somewhere. and then, in a bizarre twist, the killer returning theresa's

car to her own house. it's extremely unusual, is it not, for a killer to return to a crime scene like that? >> yes. >> because usually people commit a crime and then they want to get away. >> absolutely. -- who was living there, and then the fact that he'd be safe to come back. >> by removing her body, it buys him time. so, that's the time we believe that he can do all the things that he needed to do in the house. >> and what he apparently did in the house was to start cleaning up, as evidenced by paper towels, trash bags and spray bottles left in teresa's kitchen. how often are you at the scene of a homicide we are the killer tried to clean up after himself or herself? >> it's not that often. and when it does occur, it's

very bush league -- this was different. >> this was different. it was methodical. it was slow. it was thorough. >> he spent a long time cleaning up. >> but who would know so much about teresa theresa to know that no one would discover him if he took the time to clean the house and when had all this occurred? detectives learned that theresa had last been seen at work at the rio on tuesday, two days before friends had gone looking for her. a good citizen, she had gone to vote at this church just a few blocks from her house at 5:30 p m, then made some calls, speaking to her mom back in niagara falls, about 6:30 pm. and what did she say to you in that conversation? >> i'm tired, and i'm going to have my macaroni and cheese and i'm going to rest. and i will talk to you tomorrow. >> but an hour later, at 7:30 pm, when theresa's cousin angela called, her phone went unanswered. >> so, we had, basically, an hour window between the mother 's phone call and angela trying to call her and not getting her. so, there really wasn't an

explanation other than, she had already been attacked, for why angela's phone calls were not being answered. >> so, police believe theresa insana was attacked between 6:30 pm and 7:30 p m tuesday evening. it was now thursday. her attacker had a nearly 48 -hour head start. as word spread, theresa's best friends could not believe what they were hearing. >> i think, at that moment, i just knew something horrible happened. >> friends talked with police, hoping to provide clues in theresa's disappearance. investigators started reading theresa's diary, which was found in the house. and grace carducci remembered something theresa had told her when grace was visiting six months prior. >> one morning we got up and we were drinking coffee. and she's like, i can't put my finger on it. but sometimes, grace, i will go to work, and i will come home, and my dvd player will be on. or there will be a different

station on the television then from what i left it on. >> did she saying anything was taken? >> nothing was taken. and she said, i just have this feeling that somebody was in my house. >> do you know if she had her locks changed? >> i don't believe that she did. >> detectives followed up every lead. canine units were called. and as police -- the whole zip code which turned upside down. but experience told the detectives that any news they received about theresa was unlikely to be good news. >> we were just waiting for the call. >> that someone had found her body? >> yes. >> days dragged by. >> i remember going to church every day, and saying, please let us find her. i don't know what i was hoping for. but i just wanted us to find her. >> and then, nearly a week after detectives believe theresa insana was killed came the news police were waiting for, and that theresa's family and friends were dreading. >> a painful discovery's about to end one mystery, but launch

another. who could possibly be behind this? coming up -- "dateline"'s unsolved case squad with a dramatic theory of the crime. >> -- and you are holding on to that towel rack. >> when "dateline" continues --

♪ ♪ ♪ >> six days after theresa

insana failed to show up for work at the rio in las vegas, her father gerald was reciting catholic prayers, marking all saints day. >> i will never forget it because i'm sitting there, praying, this litany of the saints. and i turn to and murray, and i say, theresa is going to be found today. because today she became a saint too. >> and that very day, theresa's parents and her best friends received a call from las vegas metro homicide detective marty wildman. >> he called me and he said, grace, we have theresa. i know it's sad news. but we have her body. and i just did not want you to suffer anymore. >> it's just awful. the most awful thing. theresa insana's body had been found just three and a half miles from our home, near a golf course. >> her -- wrapped her body in towels and blankets. and carried theresa down a

steep, rocky embankment, and left her in a large covert, in standing water. an autopsy showed theresa insana had died by strangulation, and possibly, she had been sexually assaulted, though the medical examiner said the evidence was not conclusive. >> -- an act of anger by someone that was mad at theresa? was it staged? >> was somebody trying to make it look like a rape -- when it was something else. >> it's a very good possibility. >> and with the discovery of theresa's body, three things were immediately clear to detectives. first, that's tiny piece of metal found on the stairs of theresa's apartment? it was apparently torn from the camisole she was wearing at the time of her murder. secondly, the blankets around her body came from her home. but police believe the rope and duct tape used to bind her body did not.

it had been brought to her house by her killer. and finally, that blood in the bathroom matched a new spot of blood found on theresa's camisole. it also came, police believe, from the killer. >> i, go we've got a bad guy and, we've got a bad guy we who left a print. >> this has to be left by the -- >> absolutely. >> but whose blood was it? with a backlog at the vegas crime, lab dna test results were still months away. so, in that first days after theresa's body was found, detectives began looking at where they could learn from other evidence, like where her body was dumped and whether they were looking for a killer or killers. how many people committed this crime? >> i believe that, just from our investigation, it was a one person crime. where we found theresa -- makes that a little bit if he,

if only because it was rough terrain. >> i believe it was more than one person. i think that, based upon where the body was found, 25 feet of rocks walking down that -- >> you would have to have some help? >> i would think. because we walked down there to view the body. and it was iffy walking down there with a notebook in our hand during the day. and this is the nighttime. >> and carrying a body. >> and carrying a body. >> theresa insana had been dead for several years when las vegas metro homicide granted unprecedented access to "dateline"'s unsolved cases squad, sharing information from the files of an open case with our experts. >> dwayne stanton, retired homicide detective from washington d. c., investigator shonda levy, and yolanda

mcleary -- ,. -- specializing in cold case murders. how many people, you think, committed this murder? >> i think, by where the body was located in the -- i'm going to support two. >> i think it's one person committing the murder. and then, i agree, clearly, someone had help. >> what happened inside that hill's house? >> possibility -- we know for a fact that, at some point, theresa -- steps -- i think what theresa attempted to do to do was to secrete herself -- wait for her attacker, or attackers. once inside the bathroom, there's a towel rack that has been moved. and as you can see, the bracket is missing as well. yolanda, turn around -- towel rack -- this wall -- grab here -- you are holding on to the towel rack and -- the towel rack probably came

off of the wall. the person that was behind her, pulling on her -- >> gets it in the face? >> gets hit in the face -- >> or hit in the head or -- >> -- the blood spatter, and the mirror -- >> and the baseboard -- team agrees. the evidence of the crime, as well as moving theresa's body out of her home, using her car for transport, and returning to clean up the crime scene, together, strongly suggest this was no random murder by a stranger. has this person ever committed murder before? because clearly, some of the things that they do show some sophistication. >> i don't think that the person that has committed murder before or they may watch a lot of murder movies and -- think they know how to do it. >> unfortunately, for them, they thought of things that were much more advanced let's move the car. let's make sure we get the body out of the house. but they forget the basics.

a person's cell phone is sitting there. >> we know there's not another crime involved, let's, say robbery, because nothing is missing inside this house. nothing is missing other than theresa. >> it really limits your pool of potential suspects. >> we look who has a grudge -- who stands to benefit? who >> doesn't like? or >> who doesn't like her -- >> coming up -- police have a date with the ex, theresa's former fiancée. lled thyroid eye disease, which should be treated by a different doctor. see an expert. find a t-e-d eye specialist at isitted.com

get over here kids. time for today's lesson. wow. -whoa. what are those? these are humans. they rely on something called the internet to survive. huh, powers out.

[ gasp ] are they gonna to die? worse, they are gonna get bored. [ gasp ] wait look! they figured out a way to keep the internet on. yeah! -nature finds a way. [ grunt ] stay connected when the power goes out, with storm ready wifi from xfinity. hi i'm jessica layton. and see migration in theaters now. with a look at the hours top stories. at least five members of the iranian guard were killed in an attack in damascus, syria yesterday. the syrian state news agency blamed israel for the attack but nbc news has not yet been able to verify that report. and here in the u.s., at least 16 people died from incidents related to this week's arctic blast. temperatures were expected to reach the teens in chicago, and st. louis this weekend. the wind chill made it feel as low as minus 30 degrees fahrenheit. across several parts of the northern plains. and now let's get you back to dateline! dateline

>> welcome back to "dateline". i'm andrea canning. i'm andrea canning. less than a week after theresa insana disappeared, police found her body in a ravine. the autopsy showed she had been strangled. according to our unsolved case squad, theresa's killer or killers knew her well, and at the top of the list of people police wanted to talk to women who broke her heart. here, again, is josh mankiewicz we "lost in sin city". >> four days before theresa insana's body was found on that terrible monday morning in november, 2004, it was her coworkers from the rio, who first went to her home to check on teresa theresa. and then, when they can find, her alerted police. among, them theresa's lifelong friend and former roommate melissa match. >> i couldn't wrap my mind around whoever wanted to hurt her.

>> police ever asked if she was ever involved in anything illegal? >> right, no. >> they asked about boyfriends? >> they did. >> in fact, theresa's former fiancée was one of those coworkers who was first to enter the home that day. his name is jeff fenton, and he once lived in that house with theresa. but he also broke her heart just months earlier by breaking off their engagement right before the wedding. >> -- everything i can so that -- you guys -- >> when questioned by las vegas police, jeff fenton said he had played no part in theresa's murder. he said, he tried not to touch anything in the house or garage, but theresa's the car was still parked. >> i said, i don't -- the hole -- out -- really scared i was going to find something.

>> police needed to know as much as possible about jeff, a man who seemed to be a bit of a mystery to most, i've been 30 rolled market divorced market analysts four seasons entertainment properties, which included the rio. he and theresa had got engages two months after they started dating in 2002. shocking to many of her friends and family members -- >> jeff seem like a good guy to you? >> i really believed at first he was quite a nice, wonderful man. it's who she wanted. he asked for my blessing. i gave it to him. >> but those closest to the couple saw something odd in jeff. he seemed to be constantly under the weather. >> he came for a week. and every day he had an ailment. god can strike me did. >> he always complained a lot of headaches and that he was stressed. and he had suffered panic attacks a couple of times.

he stayed around houma lot. >> and theresa, who had been very social, state at home and to take care of him. >> she certainly not going to go out socially if her fiancée is sick. >> jeff and theresa were engaged for a year. then, just five weeks before the wedding which had to be held back in niagara falls, jeff had abruptly called it off. >> he basically came to her one sunday morning and said, i can't do this. and theresa we stay very taken aback and completely devastated at that time. >> theresa was heartbroken, as evidenced by this entry in her diary. >> i have never felt so crushed in all of my life. my life is in uproar. i still wish that this was all a horrible dream, and one day i will wake up and everything will be okay. i have no real answers, nothing to go on, just my new white dress hanging in the closet for me to stare at and wonder. >> i think she was just so sad. and that was when she shot appeared to give some signs

that i should have seen before. >> what did she say the signs? where >> she said a girl's name on the color i.d., someone she had worked with. and i think there was some thought there that maybe there was something going on. >> and apparently, there was. shortly after jeff fenton broke up with theresa, he began dating that very woman whose name had been found on the collar i. d., another coworker at the rio named melissa paul ball. >> teresa ever express how uncomfortable it was to work with both her ex-boyfriend, and her romantic rival in the same office? >> it was not an easy situation for, her every day she had to go into work and see the man that broke her heart and then have to look at melissa. she always would say to me, i'm trying to be a better person and not allow it to bother me. >> and as the months passed, jeff and theresa where at least civil to one another. when we, can just two weeks before the murder, jeff agreed to take care of theresa's dog. and he slept over at her house when theresa had to work

overnight at the hotel. and on the day police believe theresa was murdered, she did tell her friends something that made investigators pay close attention. >> she had come to my office that day. and we were chatting. and she had mentioned that she had exchanged some words with jeff. like, i confronted him, and i said this to him. and that was really it. >> what was the argument about? >> honestly, i don't really recall. i just sort of tried to be the supporting friend and say, don't worry about him. just ignore him. just move on with your day. >> did you have something to do with this? >> now. >> when he was questioned by police, jeff said that tiff never actually happened. >> you had to fight on monday? >> -- >> no verbal argument where another coworker says -- on monday? >> no. >> no argument monday?

>> there was another reason detectives were suspicious. theresa's body had been found just two miles from jeff fenton 's apartment. but police soon learned he had an airtight alibi -- jeff and his new girlfriend were buying a car. and police believe they were at the car dealership during the exact hour when theresa he was murdered. >> this whole process just seems so unreal to me. >> still, detectives thought jeff fenton, the man who had had panic attacks and was described as highly stressed, did not seem stressed at all by the murder of his former fiancée. >> it's just really upsetting. i'm upset. >> here's the thing i don't understand. i get upset -- i'm upset. >> yeah. >> okay? you, right now, to me, don't appear upset. you are like this -- flatline. okay? and you are saying, watch me, i'm really upset.

you know? why is that, that time getting that from you? it's just -- nothing's bothering you. >> i just don't think i've been able to process everything that's happened. >> one possible reason for jeff fenton's flat affect? he was taking anxiety medication. another? he had just lost his former fiancée and was confused by all the questions because he was not involved in her murder. still, police kept looking at those close to theresa as they search for answers. >> coming up -- >> there was no way in hell i would ever -- >> a new girlfriend makes an entrance and a dramatic exit -- >> how many people have you seen get up in the middle of a polygraph and run out of the room? >> it's unusual what she did. >> what will be unsolved case squad make of this?

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ask your doctor about once-daily trelegy for copd josh mankiewicz (voiceover): november 2004, theresa insana came home to rest in niagara falls, new york. her friends and family were living with equal measures of agony and bewilderment. who had killed theresa? and why? >> theresa with a good person. she did not do anything bad to anybody. they would be no reason to kill her >> and as their grief

settled in, theresa's former fiancée, jeff fenton, was being questioned about the murder. >> -- something that i had nothing to do with -- >> also questioned was fenton's new girlfriend, melissa ball. she was 23, and worked with jeff and theresa at the rio. >> -- scare you or anything, but your name has come up as -- a person that we need to talk to. >> first, melissa ball confirmed jeff's alibi, saying they were both at that core dealership the evening theresa was murdered. >> he was with me all day tuesday and tuesday night. he was with his little sister and me wednesday night. and there's no way in hell he would never hurt that woman. >> but melissa ball also admitted to police that she did not exactly favor jeff's decision just two weeks before the murder to sleep over at theresa's house to watch the dog while i theresa stayed at work. >> it upset me. because, in the relationship,

she made him -- and that's what she was doing again. >> i think the fact that jeff came over and watched the dog and state and slept that theresa's house was definitely upsetting to melissa. >> and -- not there at the time? >> that's what she's told. >> you maybe think she maybe thought, theresa is there? >> -- jeff -- stay over at the house, here's the key. >> there's just still -- between jeff and theresa that we believe melissa didn't want. >> especially, thought to tech teams, a new girlfriend who, as melissa had -- days before, learned she was pregnant with jeff's child. if move most murders involve money or love, detectives thought melissa ball had reason to worry. after, all just first marriage and ended in divorce. he left theresa just weeks before their wedding, anomalous

was pregnant and wanted to get married. what woman wouldn't worry? but when melissa talked to police, they felt her demeanor was not that of someone who was shocked by the apparent random and senseless killing of her coworker. >> did you and this theresa have some sort of argument or words exchanged on monday at work? >> never -- >> -- here is a woman that she sees every day at work, and she's unconcerned, generally, at all. >> generally people are pretty upset? >> yes. you can't imagine the number of people from the rio that called and wondered if it was someone -- >> and she wasn't worried about that? >> she wasn't worried about anything. >> four months later, jeff and -- would return to vegas homicide for a polygraph tests. although the tests are not admissible in court and do not prove someone committed a crime, here are the findings. when asked if they caused, theresa's death, and if they

knew theresa was dead before her body was found, the examiner found both jeff and melissa showed deception. but, just as interesting was what melissa did towards the end of the test. >> she got upset and grabbed her stuff. and she was crying and was out there. >> how many people have you seen get up in the middle of a polygraph and run out of the room? >> most people stay. it's unusual to do what she did. >> tell me if i'm wrong. but generally, innocent people want to stay and answer every question. >> they want to clear up all the -- >> whatever takes to convince, you i didn't do it. >> though, melissa did at one point, seemed to sympathize with theresa's having been jilted by jeff. >> i know how i reacted when -- after a couple of months. and i couldn't imagine what she was going to. so, i -- >> our team was also interested in how, at another point, melissa referred to theresa not by name, but has that woman. >> there is no it way in hell he would never hurt that woman. >> this is someone who worked with theresa. and obviously, they are both

romantic rivals at points in time for jeff sufficient affection. >> okay. just because you didn't like her doesn't mean you killed her. >> but what's fascinating is -- that woman. it shows a level of detachment and, to me, anger and hostility, that we would think might have existed while she was living. but this -- brutal murder -- >> and yet it still exists. >> that's your response? >> of course, people do react in different ways to polygraph and to news i stunning as that of a murder. as for jeff, it's what happened after the interview that got our team's attention. >> there's a point to during jeff interview with police, where they leave the room. and jeff is sitting there like this. >> i love it. >> what does that say to you? >> i love it. what that says is, oh, my gosh, what have i got myself into? >> actually -- it's the first since of emotion out of him after -- >> 45 minutes, 50 minutes --

>> that's not necessarily a sign of guilt. >> maybe what he's concerned about is, he saying, you know what? i didn't commit this murder. but i the more i'm, here i've got a terrible feeling -- might be involved. >> right. >> coming up -- a new development from the crime lab. will it mean a new theory about the case? >> could this be a murder for hire? >> absolutely. >> absolutely. >> it very well could be. >> a crucial piece of the puzzle when "dateline" continues --

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cases, it took more than a year after theresa insana's murder forward to come back from the cry blabbed to vegas homicide. the dna from that blood found in theresa's bathroom, and on the clothes she was wearing at the time of her murder did not come from her former fiancée jeff fenton. it also did not come from the woman who, a month after theresa's death, the came

fenton's wife, melissa bell. when you get the dna results back, were you guys surprised? >> i don't think we were necessarily surprised. we thought it was a possibility that it would not be him. it kind of made his lean towards more and that melissa was calling the shots, and jeff might have found out after the fact. >> do you believe jeff fenton had something to do with this? >> i do. i do. >> that's not his blood at the scene. >> he knows something. and his new wife noticed something. we just need to find out that one person that they know or somebody else knows. >> maybe he is not involved. >> it's a possibility. just the actions, the interviews -- hard time really swallowing that that he's not involved. >> it may well be that either neither geoff nor melissa had any involvement, and to this day, neither has been charged with any crime. through his attorney, jeff fenton declined our repeated request for an on camera interview. and melissa ball fintan did not respond to "dateline"'s

requests for comment. the one thing we know is that there is no prosecutable case right now against jeff or melissa. they had an alibi. and somebody else's dna is at the crime scene, and on the victim's body. >> there's not enough probable cause at this juncture. >> you have a very interesting case, with a lot of evidence that points certain ways, and then a giant missing piece. >> i completely by that there was some tension between melissa, jeff, and theresa. there's a big jump from that to murder. >> there are enough homicide cases, josh, that there is no real good reason for any of them. >> i think the mistake sometimes that people make is, when they try to look at motive as being always reasonable, always a, always clear. it is not. >> could this be a murder for hire? >> absolutely. >> -- >> it very well could be. >> -- this is somebody that either knew her or was employed by somebody that knew her, and

wanted her dead. >> what's it going to take to solve this murder? >> it's going to take, probably, a dna hit on this profile, or if somebody actually starts talking. >> i think dwyane will tell you, as a homicide investigator, you want to be good. you want to be thorough. sometimes your best friend isn't hard work. >> luck -- >> its luck. somebody coming forward with information, someone -- >> detectives have run the dna through the national database. there is no matches, yet. but detectives are still waiting. >> you guys fantasize about the moment you are going to be able to call the insana family and say, we -- unrest? >> -- a tremendous day -- hopefully, before i retire. >> we will get what we call a full loaf. that means a full confession out of the sky. -- no reason that his blood should have been there. he will confess. we just need to know who he is.

>> detective -- retired in 2017. and the question of who killed theresa insana remains a mystery. when we sat down with her, and marie insana we still faithfully placing calls to investigators, refusing to let her daughter's murder be forgotten. >> how often have you talk to the police? >> about every couple of weeks. and i am a pain. and i am a nuisance. but i am a mother. i don't know if it's going to happen in my lifetime, or joes, but i believe it will happen. >> high school graduation -- >> theresa's friends too live for the day when an answer will come. and until then, they will remain as loyal to her memory as she always was to them. >> we know that it's not in our hands at this point. it's in god's hands to bring this person to justice, and that i will never give up and. i truly believe in my heart of hearts that this case will be solved. >> teresa's best friend, her

father, died in 2021, never having received those answers. it was clear when we left spoke that there will always be a hole in his heart. >> god, she was my lifeline. i loved her so much. i love her now. i feel with her, her essence and presence was so strong, that she is still with us today. but, i cannot talk to her. i cannot hold her. i cannot kiss her. that is what saddens me the most. >> that is all for this edition of dateline. i am andrea canning, thank you for watching! for watching >> hello, i'm andrea canning. and this is dateline. >> i felt like it was a hollywood movie. >> it was of all the executive and a doting dad. >> he was very loving and concerned about his kids. >> in the midst of a nasty divorce with a bitter