When donna and walter bernadzikowski met at a church social, talk of a family even preceded the engagement ring. He used to scare the girls away by saying he wanted 12 children. And i said, well, i always thought i wanted to have 12 children. He says, oh, my god. Reporter they didnt have 12, but this devout Roman Catholic couple did raise their five in a baltimore, maryland suburb. Heidi, the only girl in a sea of brothers. When i hear that, i think poor heidi. Yep, yep. Reporter growing up with all those boys. Well, and we had friends that used to say to us, oh, she must be treated like a princess. And i said, are you kidding me . She had to be just about tough as they were. And she kept them in their place too, i mean. She wasnt treated like she was a Little Princess thats for sure. Reporter heidi grew up to be a happy, outgoing, athletic girl, surrounded by friends. It was a noisy, loving family with strict rules. Everyone at the table for dinner. Mass on sunday and no back talk. Heidis brothers frank and harold. Reporter true that your mom was known to wash out a potty mouth with a bar of soap . Or was that a metaphor . I got it. True. Reporter did you . True. Yeah. They were very strict. Definitely had a bar of soap from time to time. Reporter as she grew into her late teens heidi started to bristle under her parents strict house rules. By 19, she, the next to youngest, became the first to leave the family nest. But the grass wasnt greener. Right away, reality offered up a deadbeat roommate; and a succession of lowpaying jobs that evaporated like the morning dew. And yet she could always count on her girlfriends to buoy her up. And it was one night with her bffs shooting pool she caught the eye of a guy holding a cue stick. It was Stephen Cooke. They were shooting against one another. And he noticed heidi in the bar. Reporter kim is Stephen Cookes sister. The first night they actually went home together. And three days later, they moved in together. Reporter fast. So its pretty reporter fast romance. It was really fast. Really fast. Reporter stephen was five years older than heidi. His sister says he could be quiet and shy but always wanted to be around heidi. They did everything together. I dont think they that they really did much without each other. Reporter in 1998, stephen and heidi moved to this rental townhouse in dundalk, maryland. Stephens dad steve sr. Says after living together for nearly two years, the couple was talking about taking the next step. Was it your understanding steve, they were going to get hitched . Yes, in vegas and every time i talked to them that was the their plans. It never changed. He loved her. Reporter the timing seemed good. Heidi had just gotten a promotion at the Insurance Company where she worked. She was finally a 9 00 to 5 00er after years of temping. She was just Getting Started or getting settled into a niche when things happened. Reporter strange things that rattled heidi. In april of that year, it appeared someone was trying to break into their townhouse. There was chipping around a lock on their basement door. Looked like the doors had been monkeyed with . Yes. Reporter not long after that discovery of mischief on the locks, a stranger knocked at the front door one night saying he was forming a neighborhood block watch. He scared heidi so much that she told friends. And described the stranger as africanamerican with a tattoo. Stephen demanded new locks and keys from the townhouse management. They were installed on april 19th, 2000. The very next evening was when it happened. Are you sending somebody . Yes, i am. Just send somebody. Im going to. Just stay with me okay . Reporter an officer dispatched to their home saw heidi on the living room floor. Her boyfriend leaned up against the wall, cradling her, and crying uncontrollably. It appeared shed been strangled, her throat so severely slashed her blood had dripped through into the basement. And there was Something Else something mansonesque, scrawled on the wall in red lipstick above heidis body was the number one. Reporter when we come back a was a killing keeping track of his victims . Shes number one and get ready because here comes trouble. Exactly. And a possible suspect. Im thinking maybe this is our guy. Butcher. Heidis killed with a knife. Sorry about the holdup, folks. We have some congestion on the runway and im being told itll be another 15, maybe 20 minutes, and we will have you on your way. Runway models on the runway . Surprising. Whats not surprising . How much money evan saved by switching to geico. I would not wear that lace. Hmm, i dont know . Fifteen minutes could save you fifteen percent or more. You get to do the dishes. Ed. Bring em on. Dawn ultra has 3 times more greasecleaning power. A drop of dawn and grease is gone. So find a venus smooth that contours to curves, the smoother the skin, the more comfortable you are in it. Flexes for comfort, and has a disposable made for you. Skin smoothing venus razors. Reporter a female Police Officer was the first on the awful scene. Shes seeing Stephen Cooke, holding heidi up against the wall. Hes got her wrapped in his arms. Reporter Stephen Cooke, Heidi Bernadzikowskis livein boyfriend of nearly two years, told the arriving officer that he came home that night only to find an apparently lifeless heidi in their living room. Nevertheless, he tried cpr. At 8 58 p. M. , hed called 911. Are you sending somebody . Yes, sir, theyre on their way, sir, okay . I want you to stay with me. No, no, i cant stay with you. I gotta go with her. Reporter Baltimore County homicide detectives al meyer and gary childs arrived later that night. It appeared to them heidi had been strangled. It was obvious her throat had been deeply cut with something sharpedged, probably a knife. When you get to a scene like that, detective, does it speak to you . Does it explain itself at all what happened here . Well, it was kind of an odd scene. The living room of the house was no Real Furniture to speak of. Up on the wall to the left of where heidis body was, was a number one written on the wall. So found that obviously to be odd. Shes number one and get ready because right, yeah. Here comes trouble, huh . Exactly. Reporter those first few hours left investigators wondering was this the first signature of a budding serial killer . Was there going to be a number two . Or was it Something Else . The house was tossed, yeah, ransacked. Youve got a potential motive of burglary. And youve got the other motive on the wall of a serial murderer. Reporter 20 miles away, walter and Donna Bernadzikowski got a knock on the door at their severna park, maryland home. It was the police. And he says, you have a daughter heidi and, yes. You know, and i said, you know, whats the matter . You know, shes been in an accident . What you know, whats going on . And he said, heidis dead. It it was quite a shock, and i just started like pinching myself. Ive got to wake up from this dream. This has gotta be a dream. I think our whole world just changed. Reporter a short time later, stephens sister, kim, got a knock too. I remember running into the bathroom and getting sick. And i was kind of i couldnt i couldnt do anything. Reporter heidis boyfriend stephen, meanwhile, had been down at a Police Station the whole time being interviewed. Officers snapped this picture. His clothes bloodied he said from trying to perform cpr and then cradling heidis bleeding body. Now, how much did you know about him or the victim by that point . Not really a lot. We just knew they were in a relationship. The relationship was good. Reporter husbands and boyfriends are always persons of interest, but homicide investigators say stephen was cooperative. He told them how after his shift ended at a local lowes, he picked up heidi from her job in the car they shared, a 1994 red honda civic. It was 5 45 pm, he thought, when he dropped her off at their home. It was, he said, the last time he saw her alive. The detectives put together a timeline for the boyfriend whod run a bunch of errands after dropping heidi off. A stop at the atm, followed by a haircut, an oil change at a jiffy lube and then a swing by home depot for a plumbing piece needed to repair his sisters sink that night. He had time stamped receipts for virtually everything and turned them over to the police. Hes got a very solid alibi for his whereabouts from the time he left work until he picks up the phone and calls 911 . He does. But you still have to take into account, you know, it doesnt take long to do what had been done. You know, shes strangled and her throat is slit. You know, that could happen in a matter of seconds. Reporter after about six hours of police questioning, stephen went home. His sister remembers him being a wreck. I could certainly tell my brother was just a mess. He was devastated. I could see in his face that he was just looking attitude at him he had been crying. Reporter in the days that followed, al meyer and other investigators felt a serial killer unlikely the robbery gone bad theory too because there were no signs of a forced entry. But dna was found under heidis fingernals, presumably from her killer. Their hopes were soon dashed however when the sample turned out to be virtually useless. Detective gary childs. You had a mixture of dna from the victim and you had a mixture of the dna from the suspect. And the technology in those times was that you couldnt separate it. Reporter but detective meyer did have one suspect he was very interested in finding. That suspicious neighborhood block watch person. The dark skinned man with a tattoo whod scared heidi at her front door. And one person of interest was a local butcher. Reporter Terry Gilliam worked with stephens sister at a safeway just miles from heidis house. Im thinking, okay. Hes african american. Im thinking, maybe, you know, maybe this is our guy. Butcher, heidis killed with a knife. Reporter investigators theorized a connection through stephens sister. Theyre looking for somebody that comes to the door, did you ever go to heidis door and knock on the door . No. Saying youre from the Block Watch Association . No. Actually, i dont even know where heidi lived at. No, never knocked on her door. Reporter but the cops wouldnt just accept the butchers denials and be done with him. There were other reasons to dig deeper, they thought, including an irregularity on his work time card. A time was changed on one specific day. Its the day of the murder, one of his times is handwritten in. So the so the only day of the month . Everything else matches. Exactly. Now i have him not being able to account for himself the day of the murder. Reporter and there was Something Else heidi herself had said the suspicious block watch person had a tattoo on his left arm. Do you have a tattoo on your arm . Yes, i do. On your left arm . Yes. Terry, let me ask you now did you kill heidi . Definitely not. Reporter officials werent done yet with the butcher and heidis boyfriend, Stephen Cooke, remains a suspect too despite his receiptheavy alibi. A lot of time starts to go by. Doesnt it . Too much. Reporter at first months go by. Then years. More than a decade. No arrests. But there would be one advantage to the passage of time breakthroughs in dna technology. And that finally gave police a suspect. Who it was shocked everyone. Reporter coming up its always the husband or the boyfriend, right . But that didnt seem to be where this investigation was going. The headline here is Stephen Cooke is not the guy. Right. When dateline continues. I love you, couch. 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Three times drier, so babies can sleep soundly all night. Pampers. Reporter as the years rolled by, the Heidi Bernadzikowski murder case got colder and colder. Detective al meyer was frustrated. He was promoted out of homicide but he never forgot the case. Even when he was in another unit, he would come back up to the homicide unit and go through the file. Never got squirreled away, huh . No, no. Never. Yeah, he never he never let it go. Reporter heidis grieving family was trying to get on with their lives, remembering her on her birthday by eating her favorite shrimp alfredo, but family events were hardly the same. You couldnt fully enjoy these special occasions because youre always painfully aware that you had an empty chair. You got an empty chair, that she should be there and shes not there. Reporter heidis boyfriend Stephen Cooke was trying to move on with his life as well. He married, had a child, and landed a steady job with veterans affairs. Hes got a normal life for the first time in a long while, huh . He does. Things are looking pretty good for him. Reporter then, in 2011, 11 years after heidis murder, meyer rejoined the homicide unit and once again cracked the file. This time, he and veteran Baltimore County detective gary childs got an idea. Dna technology had progressed and we knew now that theres a possibility that heidis fingernails may contain some physical evidence. So whats the thought, lets run it again, see what happens . Yeah. The thought was to resubmit. Reporter to their surprise, the criminal database spit out a match. We got a dna hit. I couldnt believe it. Reporter but the hit wasnt for anyone in heidis known circle, even in her geography. It was a name completely off the radar from a state over 1500 miles away. They tell me its this guy, Alexander Bennett, from colorado. Colorado . And im, like, wow, thats not good. Im hoping its going to be somebody from baltimore, somebody that would be local. Did that name mean anything in heidis circle, Alexander Bennett from colorado . Never heard of him before. Absolutely not. No. Reporter baffled detectives started to dig. They called the colorado authorities and learned bennett was an unlikely suspected killer. In his early years, he showed promise as an opera singer. Performing recitals and winning a scholarship to the prestigious Manhattan School of music. After moving back to colorado though, hed gotten into some smalltime trouble. But then he did something just plain crazy. Hes a pretty talented guy, but he had some issues with the people he hung with and one of these issues was with a friend of his named grant lewis. Reporter in 2003, bennett and grant lewis had been arrested in a doozy of a scheme. Theyd called 911 and said that a friend of bennetts wanted to bomb the courthouse. But they went further, building a real bomb and planting it in his house. The bomb squad was dispatched and that friend hauled down to the station for an interview. Theyre grilling him pretty hard because thats kind of a serious crime. One of the detectives ultimately lets him listen to the 911 call and he recognizes grant lewis voice. So its not all muffled or disguised or no. No, its just he said, thats thats grant lewis, i know him. Yes. Reporter within days, lewis and bennett confessed to the whole thing. Building the bomb, breaking into the house, even uploading bombrelated materials to the buddys computer to ensure hed be arrested. Also that friend who bennett said beat him up wouldnt notice that theyd made off with his jeep. So its all a hoax, this elaborate caper to plant an explosive device in order to get him out of the house so they can steal the car . Yes. My word is harebrained. Whats yours . Yeah. Double harebrained. Reporter Alexander Bennett was sent to prison and required to give dna. Now, years later, that dna was tying him to heidis murder back east in maryland. For baltimore prosecutors Garrett Glennon and matt breault, the dna was an enticing lead but far from definitive proof. It was enough to say it looks like it came from him, you know . But we cant say its definitively his. So there was more investigation to do. Reporter so, the detectives went to work, looking for another connection between colorado native Alexander Bennett and the maryland murder. All the usual computer searches failed, but when Sergeant Meyer had the Maryland State Police mine an offline database i get this phone call from the trooper and he tells me, ive got Alexander Bennett, somebody running a wanted check on him march 30th of 2000. A maryland officer. In maryland. Im thinking, holy cow. Reporter three weeks before heidis murder, an officer had spotted Alexander Bennett walking down a baltimore highway. When a wanted check is run by a patrolman or an officer that check remains in the computer forever. How important was that . Incredibly important. Reporter detectives meyer and childs hopped a flight to denver. It was time to meet this Alexander Bennett. Coming up a suspects story, a surprise to even these experienced detectives. Thats why it is strange. These birds once affected by oil are heading back home. Thanks to dawn, rescue workers only trust dawn, because its tough on grease yet gentle. I am home, i am home, i am home so find a venus smooth that contours to curves, the smoother the skin, the more comfortable you are in it. Flexes for comfort, and has a disposable made for you. Skin smoothing venus razors. Reporter in january 2012, two Baltimore County detectives flew to denver, colorado. Their mission to track down Alexander Bennett, the man whose dna had been tied to Heidi Bernadzikowskis murder 11 years after the fact. Dna is a good piece of evidence,er ebut we want to fi out if Alexander Bennett is really a part of this. Reporter a day after their plane was wheels down, detective childs was facetoface with their target. Alexander, right . Uhhuh. Im gary childs. How you doing . Reporter at first, the detective kept it vague, trying to confirm that bennett had indeed been in baltimore at the time of the murder. The year 2000. Bennett said he was. Hed spent about a month on the streets there after being ditched by some friends on their way to a concert. I gotta tell you thats strange. Thats why it is strange. Real strange. And then not to remember anybody you stayed with or hooked up with. Reporter then, the detective played his hand. Laid out the reason for his visit. This girls fingernails were taken at the time of her death. And under her fingernails is your dna. Now theres no denying it. Reporter but bennett did have an explanation. And it had nothing to do with committing murder in a house. He remembers a confrontation that he had in a bus stop with a female in maryland, in baltimore, right around the time of the murder. I got kinda scared because, um, you know i was trying to fight back and i think i hurt her. Im not sure. Reporter the detective didnt buy it. And thought hed use bennetts story to his advantage. He presented bennett with several photographs, a Technique Police typically use to help identify criminals. Except this time, he was asking a potential killer to identify his victim. Could bennett pick out the girl from his supposed fight . Heidis picture was included. He knows that he cant give this explanation about having this fight in the bus stop and pick some other girl. So our belief is that if we show him these pictures, that he will pick her. And he does. It also, too, kind of looks like her. Reporter there was one more crucial detail. Remember the neighborhood block watch guy who frightened heidi . The one with the distinctive tattoo . Do you have any tattoos on your left arm . Yeah. Can i see it . When i saw the tattoo on his arm and he picked heidis picture out, i knew it was him. Reporter he was the block watch guy . He was the block watch guy. Reporter but they didnt have enough evidence to book him. So they decided to call in bennetts buddy from that crazy bomb plot, grant lewis, to see what he knew. And lewis was nervous. Sorry if im shaking. I was kind of shaken up. Reporter he was evasive about his friends time in baltimore, but the detective didnt buy his story. Then, because lewis had an outstanding warrant, the colorado authorities arrested him. The next day, detective childs kept pressing. I think you dont want to tell me certain things because you dont want to hurt a friend of yours. But what im trying to explain to you is nothing you say hurts him because whats done is done. Reporter at last, grant lewis cracked. He divulged a drunken conversation the two had down by a river after bennett got back. He said, i hurt someone bad. And i looked over at him and i said, i dont want to know. And he said, i think someones dead. I think thats how he said it. I think someones dead. And then he said, i knifed someone. Reporter that was it. Corroboration. 12 years after heidis murder, Alexander Bennett was charged. He was extradited to maryland to stand trial. Heidis brother frank got the news from their dad. It was another one of those things that just brings you to tears just because all that comes flooding back in. Its such a great feeling to feel like finally somethings happened. Reporter Stephen Cookes family was relieved as well. Thered been such a cloud of suspicion around him for so long that news that someone else had been arrested for his girlfriends murder felt like vindication. I was just gosh, i was ecstatic. I was, wow, this is great. Reporter this is relief. Yes. Reporter this is what weve been finally. Reporter saying for years. Its not Stephen Cooke. I was so excited for my brother. I was just so happy. He can finally put this behind him. Reporter two years later, in march 2014, both stephen and heidis families converged on the Baltimore County courthouse for the start of Alexander Bennetts trial. Grant lewis was headed there, too. Hed been flown in to testify. Hes going to be your star witness. Absolutely. Reporter but for detectives, the idea that bennett killed heidi all on his own had never made sense. They held out hope that bennett would come clean, but he maintained his innocence. Then came the morning of jury selection. Gary and i are out, getting breakfast. And garys phone goes off. And he looks down at it. He looks up at me. And hes like, alex wants to talk. And im, like, wow. Here we go. Reporter a hearttoheart with his mother had convinced bennett to spill everything. Prosecutor garret glennon. She basically told alexander if he did this, it was time to come clean. That jesus would forgive him. Reporter what they call a come to jesus moment was what it appeared that way. Reporter you were beneficiaries of, huh . It appeared that way. Reporter bennett confessed that he killed heidi. But he hadnt acted alone, he said. He had an accomplice. And that person was who else, but the states star witness. He and grant lewis, as in the bomb scheme, had developed an idea of being contract murderers. Reporter grant lewis is the brains of this operation . Yeah, it was a lack of brains. Reporter grant lewis had been sitting in a hotel room preparing to testify. Now detectives brought him in and turned the tables on him. Grant, youre in the middle of this thing. I am not in the middle of this thing. Reporter at first, lewis denied involvement, but as the detective revealed details from alexanders confession, he started to open up. Did you send him to baltimore . I didnt send him to baltimore, but i know more about this than ive said. Reporter lewis ultimately admitted to being involved in a murder for hire scam but said bennett was never supposed to kill anyone. Only to get the upfront money before turning the person who hired them over to the fbi. Did you believe that story . Not in the least. Reporter so now do you read grant lewis his rights . Yes. And the cuffs went on. Reporter but there was still one major detail left. Who hired them to kill heidi . Coming up reporter what really happened the day heidi died . A firstperson account from the killers. I was making sure that she was alive. I didnt know. Thats when i had the knife. Reporter when dateline continues. My Car Insurance with geico. Huh. I should take a closer look at geico. Geico can help with way more than Car Insurance. Boats, homes, motorcycles. Even umbrella coverage. This guys gonna wish he brought his umbrella. Fire at will howd you know the guys name is will . Yeah . Its an expression, ya know . Fire at will . You never heard of that . 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You see, medicare doesnt cover everything only about 80 of your part b medical expenses. The rest is up to you. So if 65 is around the corner, think about an aarp Medicare Supplement insurance plan, insured by unitedhealthcare Insurance Company. Like all standardized Medicare Supplement insurance plans, they help cover some of what medicare doesnt pay. And could save you in outofpocket medical costs. So dont wait. Call to request your free decision guide. And gather the information now to help you choose a plan later. These types of plans let you pick any doctor or hospital that takes medicare patients. And theres a range of plans to choose from, depending on you needs and your budget. So if youre turning 65 soon, call now and get started. Because the time to think about tomorrow. Is today. Go long. Reporter for more than a decade, detectives tried to untangle the mystery of 24yearold Heidi Bernadzikowskis brutal murder. On the morning of his own murder trial, Alexander Bennett unexpectedly confessed to an opportunistic plot. He was really a cashforhire hit man. All right, alex, you all right . Reporter bennett agreed to a deal. Tell the truth to investigators and avoid the possibility of getting sentenced to life in prison. Interviewed by detective childs, bennett laid out the bonechilling details of heidis murder. Grant was discussing about receiving money to kill somebody. Reporter according to bennett, he and lewis had been brainstorming ways to raise seed money for a nightclub. So lewis placed a coded message online, advertising discreet housecleaning services. By, discreet housecleaning, grant lewis apparently meant and hoped that someone out there on the internet would understand that to mean that they were hit men. Reporter bennett says a client did respond to the ad and offered 60,000 to kill heidi. I know from the client, from the person, you know, emphasized to grant and grant emphasized to myself that it needs to look like an accident. Reporter bennetts role was the muscle to do the actual hit. Lewis, the middle man, communicated with the client and organized everything. In late march 2000, bennett arrived in baltimore from denver. He says he waited for the signal to act. In the meantime, he scoped out his victim, breaking into heidis home by tampering with the locks, then posing as that Neighborhood Watch volunteer who so scared heidi. I do remember her answering the door. Reporter did you go to the door to talk to her more than once . It was just that one time. Just the one time . Reporter on april 20th, bennett says he heard through lewis that the plan was a go. After getting into heidis house he hid behind the front door. Now my plan was to just try to get her, and like, still make it look like an accident like, maybe snap her neck or something to look like she fell down the stairs or something. Reporter heidi walked in through the door, and bennett says he pounced. When she came in, she saw me, panicked, i panicked and rushed at her at the front and, you know, tried to muffle her scream. I was making sure if she was alive. I didnt know. Thats when i had the knife. And to make sure, had cut her throat. Reporter then, bennett said, he wiped the place down. And to throw forensics off he ransacked the bedroom and used heidis lipstick to make that number one on the living room wall. After that, bennett says, he fled. Thats it . Thats it. Reporter heidis dead. Heidis dead. Reporter detective childs pressed, who was the client . He showed bennett a photo array of six suspects. Assistant state attorney matt breault. He immediately separates four photographs and says, its definitely not these four. And hes left with two. And he takes a couple of moments and stares at them. And eventually, he says, yes, this is him. I remember him. This one. I recognize him as the boyfriend. Reporter bennett picked out Stephen Cooke. Heidis boyfriend was arrested for first degree murder. Deep in our hearts, we all had a feeling that he had something to do with it. Reporter stephens trial began in june 2015. He pleaded not guilty. Glennon and breault had the task of convincing a jury that stephen was capable of orchestrating a cold murder for hire. Their case would rely heavily on the word of one man, the killer himself, Alexander Bennett. You really had to believe this guy bennett . Absolutely. Reporter your case was going to rise and fall on that . He was going to be the star witness against Stephen Cooke. Reporter bennett told jurors the same story he told investigators, how he killed heidi. Video cameras werent permitted, but bennetts testimony was audiotaped. He decided to confess, he says, because of his faith and for heidis family. I wanted to be a human being. I wanted to give a family some type of peace. I wanted to have faith enough and to grow up into a man and to accept and take responsibility for what i did. Reporter but the question still remained. If Stephen Cooke had planned heidis murder, why had he done it . According to stephen, they were in love and planning to marry. But some of heidis friends testified that she was so miserable in the relationship, she was preparing to leave. She had asked a friend of hers for a small loan for an easy Storage Facility in an effort to move out. Reporter and the real reason for the murder, the prosecutor told the jury, was pure and simple greed. 700,000. Two months before heidis death, stephen and heidi had taken out hefty Life Insurance policies on each other. I wonder why an hourly employee at a hardware chain is buying you should. Reporter almost a Million Dollars worth of coverage . As we explained to the jury, they had one car between them, which was hers. A red civic. They are not married. They didnt have any children. And they really didnt have many belongings. There really wasnt anything to insure. Reporter so once they buy the policy, its tick tock. Correct. Reporter heidi had no idea time was running out for her. No idea what was going to happen when her boyfriend dropped her home that night. But according to investigators, stephen knew there was a hired killer in the house. He set the wheels in motion. Reporter driving her home to her death. He knew what was in that house. He knew what he was doing. Doesnt get any worse than that. Reporter but the defense would have an answer for those insurance policies and everything else. And the person to explain it all to the jury would be Stephen Cooke himself. Coming up the defense, just how strong was the prosecutions case . All you have are a confessed murderers words. Thats all. Once upon a time a little girl learned how to read. Her mighty parents kept the adventure going by reading her books that were beyond her skill level. Her mind and her imagination grew happily ever after. Reporter Alexander Bennett, the admitted killer on the stand, had spilled out a gruesome account of the plot to murder heidi. Stephen cooke, he testified, had hired him via the internet to kill his girlfriend. The motive . The boyfriend wanted her Life Insurance payout. 700,000 bucks. But stephens Defense Attorneys conceded nothing. They thought the prosecution had a weak case overall and one big problem in particular. Its star witness, Alexander Bennett. Bennett obviously had something to gain by changing his story. Our old friend, quid pro quo. Plea deal. Reporter tara lacompte and Breon Johnson were stephens Defense Attorneys. They said before the colorado mans socalled confession, bennett faced life in prison without the chance for parole. But once he cut a deal with the state to testify, he could look forward one day to walking free. So hes singing for his supper here . I couldnt have said it better myself, exactly. The less time he would spend in jail for his own deeds. Reporter the defense argued another glaring hole in the prosecutions case was the lack of any physical evidence tying stephen to the crime. The computer in the house that stephen and heidi shared was never taken in as evidence. Its a digital crime at heart. Not in this case. Not in this case. What happened . Heidi and steve did have a fairly new desktop computer, and that was never seized by the police. So to this day we have no idea what that hard drive on the home computer wouldve shown . No. So your guy is being charged with a contract killing, but nobody can produce the contract . No. Reporter not only did investigators not have any computer records. They didnt have a record of bennetts plane ticket, phone records, credit card receipts. Eyewitnesses who saw bennett and cooke together. Not even the murder weapon. Stephens sister kim. All you have is a confessed murderers words. Thats all. Theres not one piece of evidence in this whole entire trial that points to stephen, other than the confessed murderer and these detectives with, oh, their belief. Reporter and when it came to motive, they turned the case on its head. The defense version this isnt about stephen searching for a contract killer online, but rather heidi look for love on a dating website and finding Alexander Bennett, who surprised her by showing up in baltimore. We thought that he met her online, came here to be with her and she rejected him and he killed her. It made sense to us. It made sense with the forensics. It made sense with the physical evidence. Reporter to back up its theory, the defense pointed to this police photo of heidis keys and bag. If, as bennett testified, hed jumped her when she walked in the door, how did her door keys and makeup bag end up tidily on the Kitchen Table in another room . So the bag on the kitchens tables not a trivial thing for you . No. I think she made it to the kitchen. I dont think he attacked her at the front door. Make sure she was dead. Reporter and if prosecutors thought bennett was the foundation of their case, the defense felt it had its own star witness, Stephen Cooke. He would take the stand. The bottom line is by this time, we had come to the conclusion that its bennett versus cooke. Its who you believe. For a second, i just looked at her like what in the world is going on. Reporter stephen told of finding heidi, the love of his life slumped on their living room floor that night. And then i just held her in my arms and was rocking her and crying, just calling her name and all. Reporter stephen testified the couple were planning on a future together. And he was surprised when others said that they were finished. Mr. Cooke, you keep saying that you and heidi were going to get married. But weve heard from other individuals that she was thinking about leaving you. Ive never heard anything like that until now. Reporter they were also planning for kids. And that was the reason he wanted a big insurance policy on himself. We were going to start a family. We were going to have children. And i wanted to make sure that there was enough money for heidi in case i died. Reporter he added it was heidi who wanted insurance for herself. He never pushed her to get it. Heidi then asked me if it was all right if she could get 700,000 worth of Life Insurance. And i said, fine. Reporter the defense added there was proof heidi was actively nudging along the Life Insurance policy application. Shed faxed over some final documents just days before her death. Its a fact of the case, even heidis own brothers harold and frank, cant quite account for. Theres persuasive stories that she was going to leave him. And yet, theres also pretty compelling evidence that she was trying to get this insurance policy up and running. I mean, shes active in getting thats the the insurance going. Yeah. Yeah, i thats the biggest mystery to date. Thats one of the things we dont fully understand. Reporter as for the murder, stephen flatly denied ever meeting Alexander Bennett and said he had nothing to do with heidis death. Now steve, youve heard through testimony that you arranged for heidis murder via the internet. Did you do that . Not at all. Not at all. I didnt i didnt have anything at all to do with heidis murder. Why are you testifying . Im testifying because i want my family and friends and i want heidis family and friends to to know the truth. And for 15 years, they havent heard the truth. For 15 years, ive been blamed for something i didnt do. I didnt kill heidi. Reporter both sides rested. Which argument would jurors believe . Which man would they choose . The state and its key witness Alexander Bennett, the acknowledged murderer . Or Stephen Cooke, the man with a good job, middleclass lifestyle and father of a 7yearold son . The jury was out, but Stephen Cookes sister knew the verdict she wanted to hear. Hes not guilty. Theyre theyre going to say, not guilty. Theyre going to say, not guilty. Reporter but after a day and a half of deliberations, that wasnt the jury verdict. Guilty or not guilty . We find him guilty. Reporter Stephen Cooke was found guilty of firstdegree murder, hiring a longdistance killer to murder his girlfriend. I felt like i lost my breath. I just was in shock. I just could not believe thats what theyve said. I remember screaming, oh, no. Thank you, lord. Prayers are answered. Its relief, joy, and happiness and also sadness because we still dont have heidi. Reporter grant lewis, the denver middle man, has already been sentenced to life in prison. Both Alexander Bennett and Stephen Cooke was sentenced to life in prison without the option of parole. And remember the butcher Terry Gilliam . Police have totally cleared him of any involvement. And in fact offered him an apology. Its not everything, but it does its a start. It does mean something. Reporter as for heidis family, their days are all about the kids and grandchildren. And parents who believe devoutly in a hereafter, always remember, of course, heidi. Did you talk to heidi . Oh, yes. I did. What did you tell her . I just said, sweetie, we finally got the answers weve been praying for. And justice will be served. Thats all for this edition dateline. Im lester holt. Thanks for joining us. Probe. Chilling video of a woman found chained by her neck after being held captive by a serial killer. One of the rescuers is speaking out. Plus historic wins on the ice and the clay. Early today starts right now. Good morning. Im gigi stone woods. Im frances rivera. 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