here at the nbc research department, we found 71% of you want more comedy. >> four score and seven years ago, our forefathers -- >> who art in heaven. >> jay's bringing it this fall. >> buy one restraining order, get second one free. you know? >> monday through friday in primetime. >> how many stars on that flag? >> moving too fast to count them. >> jay leno show. new comedy at 10:00, 9:00 central. it's about time. this fall on nbc. >> reporter: todd and darlene, football coach, stay-at-home mom, so in love and like

everyone, there was never enough to make ends meet. >> never make up in and you're starting a family. >> reporter: then, murder. >> i heard her screaming. >> reporter: his wife suddenly killed and he was suddenly under the microscope. >> his wife was killed while she was with another man. >> reporter: father, coach, husband, now susct. >> i told them, i don't have an explanation. >> reporter: soon in another house, another victim. then another. >> the blade was cold. i could feel it. >> reporter: a masked man who struck by night, town after town, woman after woman. >> reporter: they were terrified. they didn't noah to do. >> reporter: a husband under suspicion and someone stalking victims. >> he was looking to take somebody. and i was so scared that person was going to be me. >> reporter: what happened next would stun them all. >> this is the kind of stuff you'd expect to see, you know, on the movie of the week. >> reporter: a stranger in the

house. captions paid for by nbc-universal television >> reporter: good evening, welcome to "dateline." i'm ann curry. a case that baffled investigators in three different states about women who were attack in the night. the crimes may not have been stopped if not for one brave teenager and the bold acts of the parents. the intruder had come for them. but they had a surprise for them. there's hoda kotb. >> reporter: they are marvels of engineering, vast webs of highways and roadways spun from human ingenuity and grit, connecting distant points and strangers in the night. only no one was thinking much about exits and entrance ramps when they und her. >> her eyes are wide open and she was slumped in a chair.

>> reporter: a beautiful woman attacked in the night viciously. it looked ghastly. and personal. >> a lot of stabbing-type crimes are more personal crimes with a knife often involves some heat of passion, some type of personal animosity towards another. >> reporter: but then another woman was attacked, and then, another. >> nobody in their right mind would do that to somebody. >> reporter: people started to wonder, was a serial killer on the loose? >> it changed the whole chemistry of that town without a doubt. >> reporter: and if so, would police catch him before he killed again? >> he's psychotic and -- >> reporter: the mask is what scared me the most. so i just grabbed both wrists and i said knife!

>> reporter: a horn, not from a car or truck but a cruise ship. that's where this story beginning. darlene was hearing that horn blaring in her head as she sat on her back patio one night in 2007. she was dreaming of an upcoming trip to paparadise. she was pumped to go on this cruise? >> absolutely. >> reporter: why not. she loved adventures but never travelled to exotic locales. she had been a young bride who raised two children in harrisburg, pennsylvania with her husband, todd, a carpenter. life had been good, but tough. >> some of it was difficult. there's never enough money when you're young and you're starting a family, especially that young. >> reporter: did you work long hours? >> i worked long hours. >> reporter: back then with little money for lavish vacations, darlene had to find fun in her own pennsylvania back yard. it sat down the road from interstate 81, friends and strangers alike, always welcome,

says her daughter. >> she would try and just make everybody happy. she didn't want somebody in a corner by themselves a i loan not having a good time. >> reporter: if you were not in the mood, she would pick you up, boost you up? >> she would do something to kema you laugh. >> reporter: they'll tell you that too. they became fast friends when todd coached their boys in football and darlene entertained them afterwards in their yard. >> she liked to be outdoors. my kids told me when they stayed for the week, they spent the night in a tent down in the yard with darlene, it was cold, it was wet. and she didn't give up. they had a blast with her. >> reporter: how do you repay a couple like that for all their kindness, the coaching, the baby sitting. the answer came to chad one summer night. they were planning a trip to the caribbean when their now teenage

boys got in to trouble and were punished. >> we had to make a hard decision. we decided to leave them at home. we decided to offer to todd and darlene that we would have lost. >> reporter: it was july 11, 2007. the ger hearts and the ewalts were out to dinner when chet popped the question. would darlene and todd like to join them on a caribbean cruise. the fun would set sail in october, the busiest time of year for todd, the dedicated football coach. darlene didn't care. >> was she over the moon? >> oh, yeah, she wanted to go. >> reporter: how about you? >> it was turning football season. i couldn't. >> reporter: todd explained his football schedule demanded he be on a sport field, not a ship deck. he politely turned down the offer. >> she wasn't expecting that to come out of his mouth. it was football season, okay. but you can miss it. just this time. you can miss it. it's a week. >> reporter: if darlene was hurt, she didn't show it.

she made up her mind to go on the cruise without todd. she was still thinking about it the next night as she sat on her back patio. at around 10:00, todd came out to say good night. >> i just opened the door and said to her, hey, i'm going to bed. >> reporter: mm-hmm. >> she said i'll be up in a few minutes. i said, yeah, right. she always told me that. i knew better. >> reporter: todd went upstairs to the couple's bedroom, darlene was on the phone with chet gerhardt making arangements for cke trip. on the she was on the back patio on the line from chet. she probably never heard the rustling or felt the blade. chet heard something. a startled voice. >> she said oh my god four times and the line was dead. >> reporter: chet could see the line was active. he kept trying to get a response. >> i just kept screaming in the

phone calling her name. >> reporter: just like that, darlene's caribbean dreams of white beaches and turquoise waters had dipped forever to black. coming up, what had happened to darlene? >> all's i heard was him screaming in the kitchen and everything changed. >> reporter: everything was about to change for ly. fancy feast introduces an entirely new way to celebrate any moment. fancy feast appetizers. simple high quality ingredients like wild alaskan salmon, white meat chicken, or seabass and shrimp in a delicate broth, prepared without by-products or fillers. new fancy feast appetizers. celebrate the moment. - called c.a.r.s. or cash for clunkers. - ( car being crushed ) offering up to $4500

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so you click on the accint toolkit... you can take a picture of the damage. there's an interactive form that lets you exchange information with the other driver. it also has the ability to record the exact location of the accident. we're the first insurance company to have a claims app like this. for more innovative thinking go to nationwide.com today. my name is kathy shear and i'm on your side. >> reporter: it was just after 2:00 a.m. in harrisburg, pennsylvania. a friday the 13th, to be exact. chet gerhardt had been chatting with darlene ewold when his voice cut out mid sentence. chet raced upstairs to wake his

wife, patty. >> something's happened. darlene is not responding. we have to get over there now. >> reporter: when they arrived, all was quiet in the july darkness. they ran to the back yard. >> right from the kitchen, shining through the sliding glass doors. she was kind of slump in a chair. >> reporter: even in the darkness of the back patio, they could see it all. darlene's eyes still opened, her throat, slashed. >> darlene's dead, what are we going to do? we have to get out of here. we vo the call 911. where's todd, oh, my gosh, where's todd. >> reporter: were todd and his grown sonic who lived at home still victims too? minutes later, the police arrive entering the bedroom where todd lay sleeping. >> i was sleeping and the door opens and a guy starts screaming at me to get my hand in the air. i could just see the figures and the shadows in the doorway.

>> reporter: what did you think was going on? >> i thought nick had come home with a couple of his buddies and they were half drunk and i just thought they were pulling a joke. >> reporter: but the manueliyels deadly serious. moments later, todd's son came out of the bedroom. >> guys yelling at me, swearing, told me to get on the ground. >> reporter: both were handcuffed. todd kept asking the police who were swarming his house what was happening and where his wife darlene was. the men with badges and guns were not answeng. >> after a half hour, i noticed a person was sitting at the table with her car keys and a cell phone. >> reporter: what did that tell you? >> told me she was there somewhere. she wouldn't leave without her cell phone. you know? i saw -- that's when i got worried. >> reporter: at some point, a detective removed todd's hand cuffs and led him to another room while another trooper

talked to nick in the kitchen. >> reporter: the one officer told me that darlene was dead. and all i heard was him screaming in the kitchen. and everything changed. >> reporter: todd's son called his sister who lived nearby. she rushed over to the house, now cordoned off by crime scene tape. >> reporter: threw my car -- >> threw my car in park and get out and i realized it was true and i collapsed in the yard. >> reporter: were you thinking like who would have ever done that? >> like why. >> reporter: the family said at that moment, all they could think about was the loss of their wife and mother. they were in shock and they were about to get another jolt. >> in this case, we had a husband who was in the house who apparently didn't hear anything when his wife was killed on the

back patio while she was on the phone with another man. >> reporter: ed morsico is the district attorney for dolphin county. he was at the crime scene that night and said investigators immediately began looking at todd, the victim's husband. >> so certainly the police wanted to talk to mr. ewalt and get him out of his house, talk to him back at the police station. and determine exactly what was going on at ttha residence. >> reporter: and they did question todd hours after the murder. todd explained to him he never heard his wife as she was dying on the back patio even the upstairs bedroom where she was sleeping was feet away. oo. >> there was none to chet. he just said, oh, my god, oh, my god. he said th the phone went silent. >> reporter: but police were not satisfied. the next day, they called todd into the station for more questioning. todd said the detectives wanted to know about the sore spots in the couple's marriage.

>> they say most arguments in marriages start with money. usually that's the issue. is that the case for you guys? >> it wi be over money, bills. >> reporter: todd remembers they had checked into the couple's finances. todd said that's when one of the men made a startling accusation. >> they told me i killed her because we were having financial difficulties. >> reporter: how did they say that? >> that's how they said it. >> reporter: flat out? >> yeah. you killed her because you had financial problems. >> reporter: todd insisted he had a good job and savings. no reason to change his wife. police changed tactics, telling him they knew darlene had been intent on leaving him just before he died. >> reporter: they were saying to you, she wants to divorce you, you were ticked off and you killed her. >> right, yes. >> reporter: again, todd denied murdering his wife. he even took a lie detector test. okay, so you took the test. you're done with the test, you're confident.

>> yeah. >> reporter: you're fine. >> i feel like, i'm thinking, now, they'll get this, they'll figure it out and they'll look in the right direction. i came in and told me i failed it. >> reporter: they did. >> yes. >> reporter: what did you say? >> i told them how could i fail when i didn't commit the crime. >> reporter: uh-huh. >> they said you tell us. i said, i don't have an explanation. >> reporter: by the end of that day, todd's family had hired a lawyer for him. he wn't going to be answering anymore questions without an attorney present. that only made investigators eager to ask more questions. >> well, we're always somewhat suspicious in law enforcement when someone asks for an attorney that they have something to hide. >> reporter: of course, there was someone with something to hide and something left to do. the road from harrisburg was pointing east, so many miles to go, so many other people to meet.

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>> reporter: in new jersey, just off of,i-,i-78 it's a little to that time forgot -- bloomsbury, the murder 100 miles west in pennsylvania two weeks earlier wouldn't have rattled nerves here, not in this little rural town where evil seldom intrudes. >> she loves it house, she loved the town she lived in. she used to say where she lived was like living in a norman rockwell painting.

she felt safe, everyone was friendly. and she's just living there. >> reporter: monica massaro, a 38-year-old felt so good about the street of victorians and colonials, she did something unusual, maybe unorthodox for a woman on her own. >> she never locked her doors. >> reporter: as comfortable as she felt in this pretty unlocked house, this beautiful woman was, in some ways, an odd fit for a town that was very low keyed. monica was anything but. >> she was bubbly and everybody flocked to her. everybody flocked to her. she could tell a story like you were there. >> reporter: her best friend say monica didn't just take in life, she devoured it. >> she would talk to 30 or 40 people a day and have serious conversations with them, interact with them. we can't do that. she would stay at 4:00 in the morning chat with them on the internet, talk to them on the phone. 'tweon d do that, you know? onhe would do that.

>> reporter: when not running her house cleaning business, monica was pursuing her passions, photography, motorcycles, rock 'n' roll. her favorite band, aerosmi. >>n the summer, every day -- she could go 14 days straight going concert to concert. from vegas to atlantic city, every day was still alive. most of us can't live like that. we have two kids, married, fulltime job. we lived through monica. she lived every day like it was her last day. >> reporter: so it was pretty surprising when monica, who lived for summer nights and friends, announced she would be staying in that last saturday in july, 2007. >> she's like, i'm tired. i don't feel like going out tonight. i'm just not that in to it. >> she was supposed to go with a bunch of friends. >> she was supposed to go with a lot of friends. she cancelled in the last minute. why did she stay home that night? >> reporter: the next day, sunday, came and went with no word from monica. when monday rolled around and

monica miss add house cleaning appointment, a red flag went up. a cusmer dialed her number, no answer. he stopped by her home, saw her parked car, knocked on the door. still, no answer. he called the police. >> this inside door was unlocked. >> reporter: the new jersey state police detective was among the first to arrive in monica's home that monday in july. he said it didn't appear as if the house had been broken into. in fact, it didn't seem much of anything had happened there, until he walked in the bedroom and saw the body of monica massaro. >> multiple stab wounds. it was evident she was stabbed inside the bed. her sheets were tussled. it was a bit of a fight. >> reporter: later, a medical examiner would determine monica had died when her throat was slashed. in the meantime, new jersey assigned a team of homicide investigators which included detective jeff noble. >> when you have a crime that

seems this personal, you're looking for those closest to her. what were you finding when you were talking to her friends. >> monica wasn't married. she was actively dating. certainly we looked very hard at who she was involved with. >> reporter: boyfriends. the list of potential suspects grew as police realized just how many friends monica had made over the years. >> she was, of course, on-line quite a bit following the -- the band aerosmith and she was active in that. there was a website that was dedicated to that that she spent a lot of time on as well as numerous people she would e-mail back and forth. and the other website that she spent a lot of time on. there's more questions than answers. >> reporter: they hoped the wake and the mourners ape tending it would yield a few solid leads. but the detectives' presence only rattled her distraught friends. >> i remember sitting in the viewing and looking around the room and thinking to myself,

could that person really be here who did this to her? you know? who on earth would want to hurt her? >> reporter: after all, everyone seemed to love monica. many in town started wondering if she had been killed be a ranger. then one of noen can's friends heard about another case that suggested monica's murder might not have been an isolated incident. it happened two weeks earlier in pennsylvania. the victim, darlene ewalt. >> my husband had done some research on the internet and he started picking up all these weird things. he was like, check this out. th is like the sath ing that ppened to monica. check that out. >> could there be a connection between the two murders two weeks and 100 miles apart? unlikely. in the pennsylvania case, investigators were looking at a suspect for the murder of darlene ewalt. her husband, todd. he had no connection to the new jersey victim, monica massaro. her killing was still a huge mystery.

then one day, as he stood in front of monica's house, he noticed a truck stop at the end of her block and the interstate just beyon the image troubled him. >> that's an area with all kinds of people from all over the place frequent that truck stop. >> reporter: it makes the case bigger. huge. anybody now. anybody driving down the street, basically. >> absolutely. that became a very -- almost overwhelming avenue on the investigation to start -- to start looking in to it. >> reporter: if monica had been murdered by a stranger, a killer who had simply pulled off the road, 'd likely be long gone by now. he'd likely be heading along that same highway to who knows where. all he needed was another exit ramp and another unlocked door. coming up -- would she be next? i heard his voice and he

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>> reporter: in pennsylvania and new jersey, there had been two seemingly fatal attacks on women two weeks apart at the same time miles away, kevin and genie mcdonuogh were going about their routines. they were unaware of what happened to those women. but they might be surprised to know it all shared something in common, it had to do with what they lived or rather what they lived near. >> reporter: could hear the cars and truck going by? was it annoying? oh. >> it was annoying initially. but then you get used to it. >> reporter: the crease in this otherwise pretty new england post card is i-495. it runs feet behind their home. it had never bothered or frightened them, their older son or teenage daughter, shea.

>> never would think of going to making sure every single door in the house is locked. it's something that never occurred to my mind. >> reporter: locked doors, security alarm, not something everybody thinks about in this quaint part of massachusetts, not even with a busy highway running through it. safety, or lack of it, never dawned on them the last sunday in july of 2007. mom, dad, genie, kevin, turned in at around 11:00 that night. shea came home an hour later. >> shea came in the back door. unlocked for her brother not knowing he had called us and said i'm sleeping at my buddy's. >> reporter: got it. but the only door unlock eed wa the back door. something else she didn't know. events playing out in her town that night. >> right below me where i'm standing. >> reporter: blocks away, a neighbor was the fist to raise the alarm about a strange man

below herbal co-ny. >> dressed in black clothing, a cap on, almost invisible. >> reporter: she called the police who came and found nothing. >> i think what he was doing was banging on the wall and on the door. >> reporter: then around 2:00 a.m., another neighbor down the block dialed 911 in a panic. something about someone dressed in black trying to break into her home. >> is he still trying to get in? is he still in the front door? >> reporter: he's in the house now. please get them here now. >> reporter: but he wasn't. the would-be intruder was gone. two hours later, it seemed the man in black finally found what he was looking for in massachusetts that night. a door that wasn't bolted shut. it was the back entrance to the mcdonough home. but the intruder didn't realize the unlocked door was about to become his undoing. around 4:00 a.m., genie and kevin were asleep in their

bedroom. their daughter, shea, in the next room. the girl remembers feeling something on her neck and waking up. >> i just assumed it was a knife. because of the blade and everything. it was cold and i could feel it being pressed down. >> reporter: did you panic or -- >> no. >> reporter: you didn't? >> no. i was thinking -- i don't know what i was thinking. i heard his voice and he spoke to me saying if i make any noise, he'll f-ing kill me. >> reporter: in the darkness, she made out the shape of a man wearing a mask hovering over her. in that moment, shea felt remarkably calm. she knew her parents re right next door. >> i just tried to make as much noise out of my mouth as i could. just like screaming but didn't sound like screams at all because of how hard it was pushing on my mouth. >> reporter: it was enough to wake both of your parents. what made you decide to get out of bed and go check? >> something told us to go. >> yeah. >> thank god. >> reporter: they shuffled out of their bedroom, opened the

door to shea's room, and stepped into a twilight zone. >> the first thing i see is a black silhouette bent over. i said, what are you doing. he turned to me. the mask is what cascared me th most. i grabbed both wrists, i said knife. >> reporter: for a moment, kevin toppled the figure, the man four inches taller and 70 pounds heavier regained his footing. >> he stood up like a bear. >> reporter: still, kevin hung on. >> instinctively, i said, okay. let go of the left hand. i never let go of the knife with the right. i put a choke hold on them and threw myself back and i choked him out, basically. >> reporter: how did you subdue him? where did that come from? >> i don't know. instinct to protect, i guess. >> reporter: kevin, his back against the bedroom wall kept the burly six-foot stranger locked in a choke hold as his wife genie grabbed the knife in the man's hand. shea jumped into action too. she called 911. she thought the man had a gun.

>> a man came in with a gun and put it to my neck and -- >> all right, just relax. is he still there? >> yes. >> all right, hold on. >> he's still up there. >> reporter: somehow kevin managed to hang on to the still conscious man until police arrived moments later and arrested him. as it turns out, the stranger did not have a gun, but he had been well armed. >> he had numerous knives, chinese throwing star, choking wire, a leather mask, a hood. >> reporter: local detective george tyros could not believe all of the weapons they pulled off of the stranger. >> trying to figure out, what is he doing in there, why is he doing this? what was he trying to do? >> reporter: who was he? the answer came soon enough. adam leroy lane, a trucker fom north carolina with no criminal nvinced lane had tried to sexual assault shea mcdonough.

they were about to search the chucker's rig parked near the house. that's when they would find it. the one thing that told them what adam leroy lane was planning to do that last sunday in july just off highway 495. coming up -- >> it sounds like something when you're watching a "c.s.i." or something, you i can't i t n' believe that. >> reporter: the needle in the hay stack. something was about to break this case wide open. been there. oooh, that's a new one! did you just... what? oh... yeahyou did. yeah. check this out. (female narrator) panties that won't ride up. that's the hanes comfort fit promise. thanks. oh no, no that, this is one's mine. oh, but it's my size... no, they're mine.

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>> reporter: at the end of july, 2007, police in a litt town in massachusetts had a mystery named adam leroy lane. they knew only the following about him -- he was married, with children, a trucker with no criminal history, and he had attacked shea mcdonough.

but then he searched his truck near the crime scene and found a dvd player with a disk called "hunting humans" still inside it. the detective charged with t case watched the movie. >> i study my prey until they got their pattern and it's easy to do the rest. >> it's the story of a serial killer with no real motive other than just to kill people. >> reporter: the detective had to wonder, was his trucker the serial killer. in the south and west in the middle of pennsylvania, a prosecutor there was dealing with ahe t o wnrd the murderfar dnele two weeks earlier. his main suspect was the woman's husband, todd. but the prosecutor did not have a strong case against him. >> the lack of physical evidence was very frustrating. >> reporter: and likewise, 100 miles east in new jersey, investigators there were trying to solve yet another puzzle, the murder of monica massaro.

they were wondering if their case had been a random attack. after all, the victim, monica, lived down the block from a truck stop and a highway. new jersey detective jeff noble. >> the next step was to look at the people who were at the truck stop particularly at the time we believe this murder happened. which again was looking -- like looking for a need until a hay stack. >> reporter: in other words, the killer thewere looking for could have been anyone from anywhere. the odds of finding their man -- staggering. yet, new jersey investigators knew of one tool that might help them -- the fbi. it runs a national criminal data base. new jersey wanted to know if there were any crimes anywhere in the country that were similar to their homicide. a knife attack near a busy highway. as luck would have it, the fbi had just received word from massachusetts about an assault there. >> reporter: they say that there was an assault on girl that involved a knife which involved

a -- a truck driver. an interstate truck driver. >> reporter: that attack in massachusetts was the one involving young shea mcdunoh and it had taken place one day after police believed monica massaro had been killed in new jersey. at first, the new jersey detective doubted the massachusetts case tied in to his in any real way. >> in face value, we were dealing with something that appeared to be much different. we were dealing with a significantly older victim than their victim. our victim was, of course, murdered. >> reporter: still, detective jeff noble and their colleagues decided to follow up the lead. they called the massachusetts police department handling the case of adam leroy lane arrested for that terrifying attack on shane mcdunough. >> this is the state police. >> reporter: they rattled off questions for the local detective. they wanted to know if he had found receipts or anything in lane's truck thatne put him nea their victim in bloomsbury, the

town that monica massaro lived and died the last weekend in july of 2007. >> the detective said wait a minute, did you say your town up in new jersey. we said, yeah. did you say the actual name of the town, bloomsbury. yeah, yeah, that's it. >> i have something here -- a receipt here that says bloomsbury. and at that point he said, what's the date? i gave him the date. and it was total silence on the other end of the phone. >> i remember we looked around. i looked at my colleagues at that point. the focus of the investigation changed, obviously. >> reporter: there it was, a receipt -- a purchase for a radar detector from a truck stop. just a scrap of paper, but it was a very promising lead for new jersey detectives trying to solve the murder of monica massaro. that receipt was proof that the man who had attacked shea mcdunough in massachusetts had

been in new jersey one day earlier at a truck top down the block from monica's home on the very nig police believe she had died. it sounds like you're watching a "csi" and they say bloomsbury and they say, wow, i can't believe it happened. this is the need until the hay stack. >> it is. >> reporter: while the receipt put him in monica's town around the time of her death, it did not place him inside the woman's home. it wasn't proof he had killed her. the new jersey detectives needed more. they needed to get their hands on anything else lane may have left in his truck, potential evidence in the massaro murder case. but there was a problem. >> learned that when the owner of the trucking company had responded to massachusetts to pick up his truck, which was secured at this private lot, he basically threw everything out. he pulled the truck up next to

the dumpster and took all of adam lane's personal belongings that had been in the truck and threw them out. >> reporter: within hours, new jersey detectives were sifting through trash in a massachusetts dump tear. they found what they were looking for. pieces of clothing belonging to lane. >> there were stains on them. however, at the time, it was black clothing, it was difficult for us to -- to really tell if it was blood or not. >> reporter: and something else -- >> there appeared to be long blond hair -- strands of long blond hair on a significant amount. >> reporter: what kind of hair did monica have, your victim? oh long blond hair. >> reporter: if tho >> long blond hair. >> reporter: if those hairs linked to monica massaro, they could hold lane. but testing would take time. what did you do? >> our best course was to

interview, interrogate adam lane at that time. >> reporter: the detectives were about to meet face-to-face with a suspect in massachusetts that had almost no reason to expect he would talk, he had ever reason not to. and, yet, adam leroy lane was about to spin a chilling yarn about a hot summer night in a little new jersey town. coming up -- >> not going to be -- >> reporter: the suspect speaks. what might that mean for a different suspect miles away in a different state. >> this is the kind of stuff you expect to see on the movie of the week. it's time to get schooled oangus third-pounders.

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hello. jeffrey noble. >> reporter: when new jersey

detective jeff noble sat across from adam leroy lane in a small interrogation room in massachusetts, he was hoping to win the man's trust. >> in fact, the first hour of our conversation was nothing more than light conversation between a couple of guys. >> reporter: that was a long time. >> yeah. >> reporter: and detective noble got to the point. he knew lane had been down the block from monica massaro's home in bloomsbury the weekend she died in july, 2007. >> i asked her a point, i said, did you assault somebody in new jersey. >> reporter: lane grew silent. at this point, the video cut out. but a separate audio tape captures lane mumbling something. >> i'm done. >> he says the words, i'm done. i interpret that to mean i'm dwup the interview. >> reporter: the moment you think you guys were done, like, oh, we -- we had the chance right there and it just sort of slipped right through our fingers? >> i did. >> reporter: legally, noble believed he had to end his

interrogation. that's when the suspect surprised the detective with his own question -- he wanted to know if new jersey had the death penalty. the detective told him the state had not executed anyone in years. lane continued. >> if you were me, meaning if i were him, the suspect, would i talk? and at that time, i said, absolutely. i would talk. and then during that interaction between he and i, it wast that point that i knew obviously for sure that adam lane was our -- was our killer. that he had killed monica massaro. >> reporter: yet the suspect had ended the inforal interrogation. new jersey detectives believed legally he could not ask lane anymore questions. with that, noble and the other investigator left. would the trucker have a change of heart and talk to him again? >> he was in the interview with

us. and as we were outside, he put his head in the window and made eye contact with him and he nodded. he went like this. >> reporter: you went back in. >> i went back in. >> reporter: that's when the investigation into monica kn massa massaro's murder took the most dramatic turn. with the camera back on, lane ahowed the detectives to resume the interrogation. yes, he told him, he knew all about the woman in new jersey. >> reporter: lane offered his version of that night in new jersey, how he went looking to rob and found an unlocked door. he said the victim fought back and accidentally slit her throat on his knife. the detective found the idea of an accident farfetched. still, adam leroy lane had confessed to killing monica

massaro. and soon he was about to find himself in more trouble. weeks after his confession in august of 2007, test results came back on the knife confiscated from adam leroy lane. one knife tested poz give of the blood of yet another victim. a woman from pennsylvania. her name was darlene ewalt. >> now we had the physical evidence we've been looking for since minutes after the crime scene investigators had arrived at the home that july. now they had that physical evidence. >> reporter: the pennsylvania prosecutor working the homicide now had a new suspect, adam leroy lane, someone with no connection with darlene ewalt, a random murder to. a prosecutor, that went against years of experience. >> this is the kind of stuff that you expect to seton movie of the week. >> reporter: pennsylvania had been looking all along for the wrong man in the killing of

darlene ewalt. her husband, todd, is now in the clear. he's still angry saying the investigators thought too quick hi the spouse was to blame. >> i thought they could have thought outsid of the box and looked at statistics. >> reporter: pennsylvania authorities said they have linked adam leroy lane through dna evidence with another victim in this state. >> he was in and out in no time. >> reporter: this woman attacked days after darlene's murder. >> sat up, swung around, grabbed for my throat because i felt enormous pain. >> report: she had been sleeping in this house about an hour from the ewalt when she felt pressure on her neck and awoke to see a man dressed in black. >> grabbing for my throat because i could see the blood spilling out on to the carpet. i'm looking to see, you know, the person to my right fleeing out the back door. >> reporter: she screamed as her panicked family called for help. later, she told police she had

never clearly seen the man who had attacked her. but now, pennsylvania investigators are convinced they can prove through dna evidence that that man was adam leroy lane. since his murder confession, the only entrance and exit ramps the former trucker has been taking are the ones into and out of court. >> because i am guilty. >> reporter: in december of 2007, adam leroy lane pleaded guilty to assaulting shea mcdunough in massachusetts and received a 25 to 30-year sentence. >> he cut the victim's throat from ea to ear. >> reporter: almost a year later, he pleaded guilty again in a new jersey courtroom to the murder of monica massaro. he listened as the prosecutor described the premeditated attack. no accident, as lane first described. >> how he deliberately, purposefully, and brutally cut the throat of the victim and watched as she bled to death before his eyes. >> reporter: new jersey gave

lane 50 years in prison to be served after the stint in massachusetts. the justice system is not finished with him. >> anything you would like to say? >> reporter: lane is expected to stand trial soon in pennsylvania for the murder of darlene ewalt. if convicted, he could be sentenced to death. lane declined to speak with dateline about the charges he faces. in the meantime, the relatives of monica and darlene are grateful to the detectives who have helped put lane away. those detectives insist the ones who really deserve the credit here are three people who showed unusual bravery. the mcdunough's family's reaction to impending horror stop add killer in his tracks. >> i made a comment that there were angels in the house that night. i frmly believe it. >> i definitely believe it. >> reporter: what kind of angels? >> could have been the spirit of the two women he had just killed, darlene, monica. i just feel the circumstances

and the way they played out and all of the things that could have happened that didn't happen and the things that did happen, there's no other explanation to me. >> too many circumstances. i feel he was sent there by god to be stopped there. and you can hear more about how the family stopped adam leroy lane on our website. the address is dateline.msnbc.com. that's all for this edition of "dateline monday," we'll be back again for "dateline" friday at 9:00, 8:00 central. i'm ann curry. all of us here at nbc news, good night. say to me,ients "all you insurance companies are... "you know, all you do is you take my money. "and then, when i have an accident there's a problem." jackie walker, nationwide insurance nationwide does offer what's called "accident forgiveness" and it means that if you do have an accident your rates remain the same. get "accident forgiveness" and your rates stay the same.