(ROARS) (SCREAMS) Tonight on 20/20 ` it's the season of the clown. Stephen King's 'It' is scaring up a fortune on the big screen. But is this the mild-mannered face behind a real killer clown? In the news again, a break in a cold case after 27 years. MAN: New developments in that cold case... MAN: ...called the killer clown case. WOMAN: ...charges of first-degree murder. Police are looking for an assailant who was wearing a costume. Not just a costume ` a clown costume. A woman was shot at her front door. My heart dropped. You're just handing them balloons and flowers. Your intention is to shoot someone who has a smile on their face. Right here, tonight, 20/20 on the case, taking to the skies above posh Palm Beach county where they've never seen a bizarre murder like this. She said to her parents, 'If something happens to me, Michael did it.' But was it her husband, Michael, or someone else dressed to kill? We found the woman who most likely sold that costume. He wanted to buy a costume, and I said, 'Can you come back tomorrow?' 'No, I know exactly what I want. Can I come in?' And what that person may have wanted was murder. How could a case that was so notorious go unsolved all those years? Copyright Able 2017 Kia ora. I'm Carolyn Robinson. Welcome to 20/20. Tonight, we're looking at a cold case murder that hit the headlines almost three decades ago. The shooting of Marlene Warren in 1990 was quickly dubbed 'the killer clown case'. The reason for that was simple ` the killer was dressed as a clown when he or she shot Marlene at close range in her own home. Now, at the time, police had their suspects but they didn't have the evidence. In fact, it took them 27 years to be able to finally make an arrest. Here's reporter Deborah Roberts. (CALMING MUSIC) People were concerned it was a mad, crazy clown... (DISTORTED SCREAMING) This is not fun and games. ...that was gonna show up at your door and shoot you in the face. It was just bizarre. If someone dressed as a clown knocked on my door,... (DISTORTED SCREAMING) ...I wouldn't open it. This is, uh, real life. What is shocking about it is where it happened, because it happened in Wellington. Wellington, Florida ` a hidden jewel in the crown of Palm Beach County, an area synonymous with power and money. The 35th president played here at the ocean-side Kennedy Compound. The 45th wines and dines at the legendary Mar-a-Lago ` 126 rooms, 20 acres. You've got the Wellington of the equestrian set where Bruce Springsteen has a house, where Bill Gates is building a fiefdom. But it's not just celebrities who are doing well in Wellington. So are most other homeowners. Get this ` many land their own private planes on a 4000-foot runway located smack in the middle of their back yard. The houses were build around a grass airstrip, and they all had hangars out back for the owners' planes. (WHIRRING) This is what we call Sunday sundown. (LAUGHS) So, you take this out every day? It take it two to three days a week when I go to the office, which is 50 miles. Some people have two-car garages; you need a three-hangar garage. Ah, life at the Aero Club ` offering the well-healed an option to arrive in style. But back in 1990, an unexpected visitor descended into the Aero Club in a style like no other. On a Saturday morning in May, just before 11am, a colourful character, dressed fully as a clown, drives into the non-gated community, heading for an aptly named street called 'Takeoff Place'. The clown car, so to speak ` a white Chrysler LeBaron. Inside, a delivery of balloons and a bouquet of flowers, gifts earmarked for Mrs Marlene Warren. She was home with her son and several of his friends. Um, a vehicle pulled up in the driveway. They noticed someone dressed as a clown exit the vehicle and approach the front door. The clown walked to the door, and then Marlene answered the door. The clown hands her balloons and some flowers. She says, 'Oh, how pretty.' I still remember this fact to this day. One of the balloons said 'you're the greatest'. The clown pulls out a gun and fires at point-blank range to Marlene's face. The clown slowly departs. And then what? Leaves. Jumps in the car... Yep, and goes. ..and takes off? That's it. Never to be seen again. (EERIE MUSIC) At the time of the shooting, Marlene's 22-year-old son Joe is at home with friends and gets a brief look at his mom's killer clown. He remembers seeing the clown's brown eyes as the clown got into a white Chrysler LeBaron. Neighbour Bill Kramer's out walking his dog and remembers a sound. I heard what sounded to me like a nail gun, a gun used in construction to drive nails into hard surfaces. The former Navy pilot sees a commotion at the bag of the home as Joe's friends run for cover. Some very excited young people came running out, saying something in the order of, 'They've shot Joey's mother.' My wife said, 'Stay there. I'll call 911.' The 40-year-old mom lingers, but there's no hope. She dies two days later. But why Marlene, a woman neighbours barely knew? She was a pleasant-acting woman. She was friendly if I'd see her in the parking lot or going down the street. We'd wave and say hello, and that was about the extent of our relationship. But to those who study crime and construct stories about it, the killer doesn't appear to be a stranger. Author Carl Hiaasen. There was something almost malicious about it. This was a personal crime. This was a very personal kind of crime. Surely this has gotta be the most recent photograph of Marlene that we've got. Her still-grieving parents say she had no enemies. Marlene was outstanding, friendly, loving, kindness. Do anything for anybody. Always courteous. Always respectful. Here is, uh, a set of three clowns. Eerily, mom Shirley tells us the family always liked clowns. In fact, here's their circus room in their home. Yeah, I kinda look at this one right here and say, 'Hey, things will turn out all right.' I feel he's sad because Marlene was killed. Did you buy these after Marlene was killed? I had 'em even before. Marlene hauntingly painted this one as a young girl. This picture here is a painting of a clown. Marlene painted it when she was a teenager, and I think it's quite a coincidence. And I'll keep it forever. That is for sure. Yeah, it's just a shame that somebody took her away from us at 40 years old. This was taken two or three years before she got murdered. She was also taken away from her husband of 18 years, Michael Warren, a self-made man. Confident ` that's the word. Very confident about everything. But former neighbour John Herring says he seemed to be a fish out of water. Rough around the edges? A little rough around the edges. Were they a part of the community? In the Wellington area, you knew almost everybody, and you would go to the country club or to the grocery store. Michael wasn't part of that. You never ran into him anywheres. As one guy described it to me, you know, he had that used car rent-a-wreck type personality. And an occupation that goes with it. At the time of the murder, Michael Warren was running a used car lot and rental car agency. A lot of the cars were not the best cars to buy. Um, it was one of those, you know, places that you went if you had really bad credit and you needed somethin' to drive. While Warren doesn't appear to be a guy looking for trouble, somehow trouble seems to find him. And things are always happening to him. His plane disappeared once, and it shows up somewhere with a broken engine. Nobody knows what happened. He had race horses at one point, and one horse shows up dead, and the guy said to me, 'He was that kinda guy.' While there's nothing in Warren's history to suggest that he or anyone in his family would be the target of murder, crime reporters from back in the day sensed something was amiss. Now, you're thinking that you're just going to cover yet another shooting. And the you hear that this is... police are looking for an assailant who was wearing a costume. Not just a costume ` a clown costume. It made sense that the murderer ` the killer ` had to have known or been associated with the family in some way. A family seemingly in crisis ` Marlene telling her parents the marriage was rocky. But the family businesses reportedly made things more complex. A lot of the properties that she and Michael, her husband, owned were in her name. And so if there was ever to be a divorce, it would have been a complicated one. The newspapers back then run with speculation that Michael may have had a mistress ` and there's this curious comment by Marlene to her parents. She said to her parents, 'If something happens to me, Michael did it.' And when something does happen to Marlene, Wellington is on edge. It was this shock of this crime, because, all of a sudden, they were betrayed in their sense of safety and security. Up next ` who is this demon in disguise? And why is Marlene Warren a target? Investigators know how hard it is to climb inside the mind of a killer. Motive? Love triangle, money, greed. It could be a lot of things. And did this costume store employee unknowingly help dress a killer clown? I said, 'Can you come back tomorrow? We're closed.' 'No. I really need this tonight.' And did that killer somehow know about the family's fascination with clowns? There are certainly plenty of questions, and we'll have the answer to some of them after this break. (DRAMATIC THEME MUSIC) Welcome back to 20/20. Tonight we are looking for answers to a cold-case killing. But it's a cold case with a difference. It's the killer clown case ` the murder of Florida mum Marlene Warren in her own home by someone dressed as a clown. Marlene was gunned down 27 years ago, and at the time, police and locals had plenty of theories and plenty of questions. As Deborah Roberts continues with this story, everyone is looking for answers. (EERIE MUSIC) How does 40-year-old Marlene Warren, married and moneyed, end up in a Palm Beach County cemetery? Detectives conduct surveillance, monitoring who showed and who didn't at her burial. There are also leads to run down which lead detectives to Deborah Offord and Barbara Castricone, who used to run a costume shop in town, one of only three in Palm Beach County at the time. In the hours leading up to the murder, Deborah recalls a persistent customer who arrives after closing time. So, you had a knock at the door? Right. And then what? She said, 'I need to buy a costume,' and I said, 'Can you come back tomorrow? We're closed.' And, 'No, I really need to get a costume tonight.' The urgency understandable if it was Halloween, but it's May, and the customer isn't looking for just any outfit. Full-on circus clown hair and make-up designed to delight ` or terrify. an afro clown wig, Bob Kelley clown make-up and a sponge nose. 'Deborah offers police a description.' I'd say probably around 5'8"; brown eyes; long chocolate hair; and jeans and a men's work shirt. Do you remember how much? I think the sale was, like, either $79 or $89. I can almost see the sales receipt. Cash? Cash. 'After lots of questions from the detectives, Barbara can no longer contain her curiosity.' Did you know why they were asking? I said, 'Could I ask please what this is in reference to?' And he said, 'Well, you're probably gonna read about it all over the papers tomorrow morning, 'but a woman was shot at her front door...' (SOBS) I'm sorry. '...by a person dressed in a clown costume wearing flowers and balloons, 'and he shot her in the face.' And my heart dropped. Those two balloons would offer up a small clue, one of them reading 'you're the greatest'. One of them was an unusual balloon, believe it or not, and it was only sold at one of the Publix grocery stores in Palm Beach County. Clerks at that same Publix tell police that the same person also bought flowers. Former reporter Jim Depalo was covering the story for the Sun Sentinel at the time. They were like, 'We know who the killer might be, 'because we saw that person come and buy the same exact stuff 'you're talking about 90 minutes before the murder.' The biggest clue of all still hiding in plain sight. Now they're lookin' for the Chrysler LeBaron. Four days after the murder, the white two-door is located. MAN: Detectives found the car at this Royal Palm Beach shopping plaza, only five miles from where the shooting occurred. There's no murder weapon inside, and, curiously, no fingerprints. Detectives meantime are searching through the car, looking for any scrap of evidence. So far, they've been relatively quiet about the new lead, but there's hope that this will be a break in the investigation. Police are reportedly quizzing business associates of Michael Warren, who confirm his dead wife's suspicions about Michael cheating. There were rumours, at least, that Mr Warren was having an affair with a specific woman that used to repossess cars for him. That woman is Sheila Keen. Sheila was a Glades girl. Sheila grew up in the small towns on the outskirts of the everglades near Lake Okeechobee. She was country, she was attractive, the boys liked her, and she liked money. She wanted a rich life. She wanted nice things. And Michael Warren could offer some nice things. It started with a pay cheque. Warren was in the business of selling cars; Sheila in the business of repossessing them from his deadbeat customers. She apparently was tough as nails. People said that she would go to any neighbourhood at any time of the day or night and pull her flatbed truck up and take a car. She was fearless. But both deny any romantic relationship. When they asked Mr Warren about the supposed affair with Sheila Keen, he denied it. It was he said, she said. Employees said they would leave for long lunches together. Slowly but surely, dark clouds of suspicion gathering in the Sunshine State. And Sheila Keen squarely in detectives' crosshairs ` especially when they get wind of this. She allegedly went to an auto parts store that she frequented dressed as a clown to entertain the owners' young children. And speaking of disguises ` the 27-year-old was married to someone who might've worn one himself. She marries a guy 20 years older than her, was a member of the Klan... and she fell in love with him. When her short marriage sputters out, police say that's when she's suddenly free to spend time with the wealthy Mike Warren. So, Michael Warren was paying for an apartment for Sheila Keen? Yes, that's` According to the police, that's correct. The other residents at the complex where Sheila lives said, 'We thought Michael and Sheila were married, he was there so often.' Detectives get a search warrant for Sheila's apartment, confiscating some of her clothes and obtain samples of her hair. They also take a long, hard look at the widower who they say stands to benefit from Marlene's murder, including a life insurance policy covering the victim, full control of the family business, plus that home at Aero Club. In all, a seven-figure possible pay-out for the grieving husband. We were riding around Wellington,... and I told him. I said, 'Mike, I don't think that you've done it, 'but I know pretty damn well 'that you know more about it than you're letting out.' And he says, 'Honest, Bill, I don't know.' Honestly, things are about to get even stickier for Michael Warren. Remember that getaway car, the abandoned Chrysler LeBaron? Police have been able to link it back to a car lot in West Palm Beach. That's right ` Michael Warren's car lot. (DISTORTED SCREAMING) When we come back, the wealthy Wellingtonites think the pieces of a puzzle are coming together. You ask him to his face, 'Did you kill your wife?' I ask him. Yeah. Well, I said, 'Did you have anything to do with it?' So why, for almost 27 years, does the case go ice cold? How is it the police would not have arrested her at the very least on that evidence? It's not illegal to buy balloons or a costume. So why was there no arrest in this case for over quarter of a century? Stay with us to find out. (DRAMATIC THEME MUSIC) Welcome back. Tonight on 20/20, we're looking at a bizarre cold-case murder from last century that baffled a wealthy Florida community for 27 years. In 1990, Marlene Warren was shot dead at her front door by someone dressed as a clown. Now, suspicion immediately fell on her husband, Mike, and the woman he was having an affair with, Sheila Keen. But police couldn't find enough evidence to charge either of them ` or anyone else, for that matter. Now Deborah Roberts continues the story. The clown-centric horror blockbuster, 'It'... My grandfather thinks this town is cursed. ...has become an international sensation this year, becoming the top horror film of all time. (DISTORTED SCREAMING) But in 1990, 'It' was real. In the weeks and months following the murder committed by a clown, the local clown economy takes a hit. Nobody wanted to hire them. The kids were afraid of them, and the last thing a kid wants to see at their party... is a clown. The Bozo backlash impacting long-time entertainers like Selim Salguero, who suddenly finds himself persona non grata. Every is very apprehensive about having a clown come to your party to an event because they didn't know who this killer clown was. Meanwhile, Michael Warren's having trouble at his job. Police are digging into his background during the murder investigation, uncovering something shady on his used car lot ` odometer tampering, the kind seen in the movie 'Used Cars'. You are not gonna find a deal anywhere like this in town. Warren is charged, but not for murder. MAN: Mike Warren is accused of 66 crimes in connection with the way he ran his failed auto dealership in West Palm Beach. I mean, there's so many aspects to this that are strange. Best-selling author and Florida native Carl Hiaasen is fascinated by all the twists and turns in the case. I don't know. Maybe there's good money in odometer tampering. Who knew? Michael Warren sure knew. He magically turned old cars new again, rolling back the odometers, adding value to the cars, allowing him to sell them for more to unsuspecting buyers. There was a very large number of cars that that had happened to. Warren's convicted on 43 counts of racketeering, theft and the odometer roll-backs. But neither he or his alleged mistress are charged in that costume-wearing, gun-toting murder of Marlene. He maintains his innocence in that crime ` and has an alibi. Michael spent a lot of time at race tracks, and he was on I95, headed to the Calder race track in Miami during the time of the murder. And he had friends with him in the car, so he had an alibi. Good news for Sheila ` she says she has one too. Sheila said that she could not possibly have committed this crime because she was out repo-ing cars at the time. But the bad news ` the evidence seems to point to her. For starters, the description from those costume shop employees who ID'd Sheila from a photo shown to them by police. If you look at this picture, do you see a resemblance to the woman you saw in here possibly? Yes. And don't forget the getaway car. Inside, it turns out some pretty compelling evidence. The investigators found a few things in the white Chrysler LeBaron that the clown allegedly had made the getaway in. There were orange fibres that could've come from a clown wig and apparently a few hairs as well ` human hair. Human hair ` chocolate brown human hair, the colour of Sheila's. And remember, when police searched her apartment, they took hair samples. Might they match? And there are those props bought by someone clerks say matches Sheila's description at a Publix, located, by the way, just 1500ft from Sheila's old apartment. They were able to potentially link her to the flowers and the balloons. So how is it the police would not have arrested her at the very least on that evidence? It's not illegal to buy balloons or a costume. And nobody at the scene could say that was Sheila Keen, cos whoever the killer was is wearing a clown suit with make-up. Bottom line ` prosecutors felt there was simply not enough evidence to get a conviction. And with that, the unsolved mystery fades from the headlines. Once the murder happened and headlines kind of died down, there were other horrific murders to cover, unfortunately Marlene kinda got lost. It didn't stay in the headlines. No, not that way. Behind the scenes, there's lots of talk about the case and a differing of opinions on how to move forward. Some of the people that were investigating the crime felt that they had enough evidence to maybe go ahead and make an arrest, and so the detectives were upset that the state attorney's office kept saying, 'No, we want more evidence.' There were reports that Sheila Keen had dressed as a clown previously at some other office event, that someone fitting her description had been seen buying flowers, that someone fitting her description had been seen buying a clown costume. It would seem that that's pretty strong circumstantial evidence. It's not about the police or the state attorney's office not connecting dots or failing in any way. Everybody worked diligently on this case. It's just... being patient enough to make sure that we'll only prosecute somebody for first-degree murder. We intend on getting justice for that victim and the victim's family, and we wanna make sure that we do it right. No arrest, no progress ` only suspicion, especially from Warren's neighbour, John Herring. I asked him, 'Did you do it?', and he said, 'Of course not.' You ask him, to his face, 'Did you kill your wife?' I asked him. Yeah. Well, I said, 'Did you have anything to do with it?' He says, 'No, of course not.' I said, 'Good.' On New Year's Eve 1997, Michael Warren has something to celebrate. He's released early after serving only three and a half years of his sentence for the odometer tampering and maps out a new life for himself. Coming up ` a neon clue. Will a Vegas wedding at the chapel of love add some heat to a very old case? So what has an Elvis wedding got to do with the killer clown? Stay with us to find out. MAN: Look around. As the Favourites come out, it begins. Observing with an eagle eye. Mastering the art of stashing. Oh, brilliant move, Gran! Cadbury Favourites. (DRAMATIC THEME MUSIC) Welcome back to 20/20 and tonight's investigation into the so-called 'killer clown murder'. When 40-year-old Marlene Warren was gunned down in her home in ritzy Palm Beach, Florida in 1990, suspicion immediately fell on her husband ` and his mistress. But they weren't charged, and the case soon fell out of the headlines. Time passed, but eventually Michael Warren and Sheila Keen reappeared in a new town with new identities and a new marriage, courtesy of an Elvis impersonator. Here's Deborah Roberts. Our story now shifts in time and location 14 years later, far from the palm trees, sunny beaches and luxury yachts of Palm Beach, Florida ` 835 miles, to be exact ` to the lovely, quaint town of Abingdon, Virginia. We kind of combine the best of both worlds. We have that small-town charm. People come here to stay and enjoy the culture, and then they go out and enjoy the great outdoors as well. And it's here in this leafy rural area that two out-of-towners buy a prime piece of property in 2004. building this 4100-square-foot home in an exclusive subdivision. And the house looks even better from the back. It's right on the lake where you can see the owners' private dock and watercraft. They're very friendly, outgoing, nice. Neighbours Brooke and Rocky Blevins become close friends with the newcomers, known to them as Debbie and Mike. He was a happy, affectionate type person. They would hug you when you go see 'em. If you needed something, you'd call 'em and they'd be there. To the Blevins, it's clear that Mike and Debbie are head over heels in love with each other. They were very close, and there was a connection of their smile at each other, the twinkle of their eye. They were very much in love, very close. In fact, Mike and Debbie even worked together, running their business just across the state border in Kingsport, Tennessee. The two operate the Purple Cow, a quirky and popular drive-through fast food joint, known for its signature Steak Bomb, fancy hot dogs and cows that greet you at the kerb. Here's Mike on the Purple Cow's Yelp page, boasting... He prided himself on that. Mike, he is a terrific cook, but they had a tremendous business. They both were the ones that prepped the food. They worked long hours. But it turns out that sociable, hard-working couple has a dark past. Mike, the friendly, burger-flipping owner of the Purple Cow, is none other than Michael Warren, whose wife, Marlene, was gunned down 14 years earlier by that killer dressed as a clown. As for Debbie, she's actually Sheila Keen, the person we suspected of being that killer clown who, despite circumstantial evidence pointing her way, was never charged with the crime. Even some of the investigators on the case were surprised that there was no indictment, because everything, sort of, lined up pointing to Sheila Keen being the clown and Michael Warren somehow being involved. But it was all circumstantial. Still, there's something astonishing authorities in Florida may not have known. When Michael Warren gets out of prison for serving more than three years on that odometer fraud conviction, he and Keen hook up in the marriage capital of the world. That's right ` Vegas. In a tasteful and understated ceremony and the Little White Wedding Chapel in 2002, Michael marries Sheila, his former alleged mistress and the prime suspect in his wife's death. The weird thing is that they hang together that long, start a business and get married as if nothing ever happened. It takes a certain amount of nerve to do it that way. And for 15 years, the two lovebirds make their quiet nest in Abingdon, just last year selling the Purple Cow and retiring to enjoy life at their lakefront home. They finally started living their lives instead of workin'. They seemed very open. He always seemed to be a happy, laid-back kind of guy. But other neighbours say they see a different side of that rough-around-the-edges former used car dealer. Vicki and John Chidester say they have a nasty run-in with Michael Warren after he suddenly shows up at their lakeside property trying to haul away rocks with his tractor. I told him to put down the rocks and get off our property. And he was saying, 'Can't we be neighbourly about this?' And I told him, I said, 'The neighbourly thing would be to call over and ask if you could come over here and do that.' He said, '(BEEP) you. What are you gonna do, you scrawny...?' I said, 'I tell you what I'm gonna do, you fat ass.' But he wouldn't get off the tractor, so he unloaded the rock. He was a bully. Somebody that thinks he's gonna get what he wants. Yes, uh, exactly. Mike and Debbie may want nothing more than to continue their mundane, low-key suburban existence. But sometimes you just can't bury the past, especially when it involves a bizarre and notorious crime involving a killer clown that's still alive in the minds of some people back in Florida. It was like an urban legend. The fact that it was never solved ` it just went on and on and on. In May, which was the 27th anniversary of the killing, my editor said, 'Well, let's relook at this.' While Marshall's writing that anniversary article for the Palm Beach Post, a breakthrough. Her researcher uncovers those startling facts on Michael and Sheila ` make that Debbie's ` new lives. She found that Michael Warren and Sheila Keen had gotten married. She also found that they were living in Abington, Virginia in the Blue Ridge mountains. The Warrens' new private life is now public, out there for all to see. Will they be able to enjoy that quiet retirement much longer before someone comes knocking on the door? Our agency received a call in regards to the murder of an individual that occurred back in 1990. Could a 27-year-old cold case end with the tears of a clown? So, are we about to get an arrest ` or perhaps two ` in this 27-year-old mystery? Stay with us. Welcome back to 20/20 and tonight's look into the notorious killer clown murder. 27 years after Marlene Warren was shot dead by someone dressed as a clown, advances in forensic science have given police a huge boost. It looks like they've finally got the evidence they need to bring in the suspect they've been chasing for more than quarter of a century. Here's Deborah Roberts. It's August in bucolic Abingdon, Virginia, where violent crime on a scale from one to 100 is a lowly 13. Sheriff Fred Newman receives an unexpected call from his counterpart in Palm Beach County, Florida. Our agency received a call in regards to the murder of an individual that occurred back in 1990. Not just any cold case, Sheriff Newman is told, but an infamous murder that made headlines in South Florida. I've been sheriff of our county for 18 years. We have never encountered any type of a murder of that nature. Florida authorities want the sheriff to track down the key suspect, that woman known locally as Debbie. Of course, Debbie is none other than Sheila Keen, now married to Michael Warren, the husband of the murder victim. They live in a very upscale neighbourhood. They kept a very low profile. Uh, they, I guess, sort of, flew under the radar, if you would. But the sheriff and his deputies are zeroed in on Sheila now. On September 26th, a trap is set after the Warrens are spotted leaving their home in their Cadillac SUV. The vehicles were strategically placed along various, uh, locations and observed the, uh, black Cadillac Escalade as it was travelling. And just as the Warrens are returning, the trap is sprung, the couple's Escalade stopped and surrounded. As her husband, Michael, looks on, Sheila is placed in custody. I did not, uh, notice anything from a standpoint of being distraught. Uh, somewhat surprised, I guess, if you would. I guess reasonably calm, for the most part. She was placed in one of our patrol vehicles, handcuffed and transported to the regional jail. Sheila Keen Warren ` not only with a new last name but a new hair colour, blonde ` charged in the murder of Marlene Warren. Another photo of the accused killer clown oddly showing her smiling while in custody, reminiscent of this mug shot, taken when she was 21, convicted for shoplifting. When the case went cold, a lot of people forgot about it. Did it ever go off the radar for investigators? No. I can tell you right now ` we probably have 300 cases that are unsolved cold cases. None of 'em are off the radar. Police in Florida arresting a female suspect. WOMAN: Sheila Keen Warren was arrested last night, accused of shooting Marlene Warren in the face. WOMAN: She remained on the run for 27 years. Sheila Warren's arrest makes headlines nationwide. The sheer novelty of a cold case involving a killer clown seemingly cracked after 27 years proves to be a huge, irresistable story. WOMAN: Detectives always suspected Sheila but couldn't prove it. The burning question ` just how do authorities say they've cracked the case that has vexed investigators for nearly three decades? They say the breakthrough was through something that didn't exist back in 1990 ` sophisticated DNA testing. We were able to, uh, do that with new technologies and DNA, and we were able to complete the puzzle. How confident are you that you have the shooter? 100%. 100%? No doubt. When you're talkin' DNA, they will be able to tell you that it's you to the exclusions of millions and millions of people, all right? Plus, the area that this was captured in can only be what the perpetrator was involved in. While authorities are intentionally vague on exactly what they tested and how, remember, back in 1990, investigators reportedly found orange fibres, possibly from a wig, and hair in that Chrysler LeBaron, believed to be the getaway car. If they found hair, the statistics are basically one in 10,000. If they found blood, great. That would give you a slam dunk, because you would end up with statistics of one in trillions. Can you really go back 27 years and test evidence for today's DNA technology and make a case? Yeah, without a doubt ` as long as DNA has been preserved cold and dry. Cold and dry. The testing has got so incredibly sensitive, so specific, there's no way out. I mean, they're gonna get results. Back in Abingdon, Virginia, shock and bewilderment after that friendly neighbour, Debbie, is charged with first-degree murder. I've been in shock ever since. Yeah, couldn't believe that ` and still don't. Just hope and pray that, uh, she's not guilty. The Blevins say since Debbie's arrest, her loving husband, Mike, has been holed up in his home, apparently in a state of stunned disbelief. Very distraught, which he would be. He, um,... told me, he said, 'You know she didn't do this. She's so kind-hearted.' I said, 'Oh, absolutely. That's why this whole thing's so hard to believe.' For Marlene Warren's parents, it's not hard to believe at all. It simply confirms their decades-old suspicion. I turned to anger when I heard that Mike had married Sheila. Angry. Uh, remembering that she killed my daughter and he marries her? You know there's gotta be something there. Talk about October blues. Now a woman accused of dressing up as a clown and killing her lover's wife is finally in custody. Oh, Sheila Keen Warren, finding herself plucked from obscurity in Virginia and extradited back to infamy in Florida, facing charges of first-degree murder with a firearm. It's a crime that's taken so long to bring to trial, state attorney Dave Aronberg was still in college when it happened. Sometimes justice can be delayed, but justice eventually arrives. Accused killer clown Warren doesn't exactly play to the crowd in her first appearance before a judge, playing the mime instead, obscuring her face with her hair, turning away from courtroom cameras. State is seeking your law, Your Honour. She later pleads not guilty. She vehemently denies any involvement. And while this all has the air of a media circus,... Thank you for being here today. ...Aronberg struck a sobering and serious tone at his press conference, announcing the state will pursue the maximum penalty. We filed the notice of intent to seek the death penalty today, just now, with the court. This is a death-eligible case. But I would bet that the prosecutors are using it to some degree to put pressure on her to plead guilty and or potentially come clean about her husband's role, if any. As for her husband, formally married to murder victim Marlene Warren, tonight he's telling 20/20 that Sheila is... Investigators are mum on whether he might face charges. Well, I can't speak specifically to Michael Warren. We're going to investigate anyone that may be culpable and will make a decision on prosecutions as appropriate. Meantime, back in Palm Beach County, there's a sense of relief that there's possibly an end to a bizarre and chilling murder case. When you heard that 27 years later, police had made an arrest, what did you think of that? I was happy, cos I think there should be justice. We felt like, 'OK, there's the end of that story that's been open and forgotten.' I think that we were just glad that, 'Wow, that's done.' It's about time that this case comes to a close, that people will look at clowns with more of a happy type of look and not some scary 'It' type of costume. Everybody wants this to, sort of, be put to rest, and I feel for her family. They need closure more than anyone else. Marlene. If you're the family of the victim, it's bittersweet because finally somebody's been arrested but the idea that it took 27 years has gotta be frustrating and a little bit perplexing as well. This is the entrance to our clown room. She liked the clowns when she was a little girl. I come in here, I think of her. Emotions still raw all these years later for Marlene Warren's parents. I feel like crying. Those nasty people. You can't tell me that he didn't know. No way in hell. She got away with it for so long. If there's a hell, I hope she rots in it. And as prosecutors continue to prepare their case and Sheila Warren awaits trial, no charges have yet been laid against Michael Warren. Well, that's our show for tonight. Thank you for joining us. Kia ora. Nga mihi. Captions by Jake Ebdale. www.able.co.nz