Transcript for Woman says she believes she may have sold 'Killer Clown' the costume
Reporr: How does 40-year old Marlene Warren married and moneyed wind up in a palm beach co. Cemetery? Detectives conduct surveillance monitoring who showed and who didn't at her burial. There's also leads to run down. Which lead detectives to Deborah Offord and Barbara Castricone who used to run a costume shop in town 1 of only 3 in palm beach county at the time. There were only a handful of us back then. There wasn't you know internet shopping like there is today, even catalogs. Reporter: 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." Reporter: 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. A Rubie's clown costume, an afro clown wig, Bob Kelly clown makeup and a sponge nose. Reporter: 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 dollars. I sort of almost can see the sales receipt. Cash. Cash. Reporter: 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?" He said, "Well, you're probably going to read about it all over the papers tomorrow morning, but a woman was shot at her front do by a person dressed in a clown costume bearing flowers and balloons, and he shot her in the face," and my heart dropped. Reporter: Those two balloons would offer up a small clue. One 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. Reporter: Clerks at that same publix tell police that the same person also bought flowers. Former reporter Jim Dipaola 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. Reporter: The biggest clue of all still hiding in plain sight. They're looking for the Chrysler Lebaron. Reporter: Four days after the murder, the white 2-door is located. Detectives found the car at this royal palm beach shopping plaza only 5-miles from where the shooting occurred. Reporter: There's no murder weapon inside, and curiously, no fingerprints. Detectives meantime are 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. Reporter: Police are reportedly quizzing business associates of Michael Warren who confirm his dead wife's suspicions about Michael cheating. There were rumors that Mr. Warren was having an affair with a specific woman that used to repossess cars for him. Reporter: 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. Reporter: And Michael Warren could offer some nice things. It started with a paycheck. Warren was in the business of selling cars. Sheila in the business of repossessing them from his deadbeat customers. And she apparently was tough as nails. People said that she would go to any neighborhood at any time of the day or night and pull her flatbed truck up and take a car. She was fearless. Reporter: But both deny any romantic relationship. When they asked Mr. Warren about the supposed affair with Sheila keen he denied it. And it was he said she said. Employees said that they would leave for long lunches together. Reporter: Slowly but surely dark clouds of suspicion gathering in the sunshine state and Sheila keen squarely in the cops' crosshairs especially when they get wind of this. She allegedly went to an auto parts store to entertain the owner's young children. Reporter: And speaking of disguises the 27 year old was married to someone who might have 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. Reporter: When her short marriage sputters out, police say that's when she is 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 lived said "We thought Michael and Sheila were married, he was there so often." Reporter: 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 payout for the grieving husband. We were riding around Wellington and I told him. I says, "Mike," I says, "I don't think that you done it. But I know pretty damn well that you know more about it than you're lettin' out." And he says, "Honest. Honest, bill." He says, "I don't know." Reporter: Honestly, things are about to get even stickier for Michael Warren. Remember that get-away 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.
This transcript has been automatically generated and may not be 100% accurate.