Marlene Warren's husband Mike had been having an affair with a woman named Sheila Keen at the time of Marlene's murder on May 26, 1990 — and 27 years later, Keen pleaded guilty to killing her.
Palm Beach Sheriff’s OfficeMarlene Warren was murdered in 1990 by a killer dressed like a clown.
“How pretty, how nice.” Those were the last words Marlene Warren ever spoke. As she was eating breakfast on the morning of May 26, 1990, with her 21-year-old son Joe, a clown with balloons and flowers knocked on the front door of their home in the private aeronautical housing community known as Aero Club. Marlene went to answer the door, likely believing that the gifts were for Joe, who had recently broken his leg.
A moment later, a gunshot rang out; the clown had shot Marlene Warren in the head. As Joe watched in horror, his mother’s killer slipped back in a nearby car as if nothing had happened.
But though Marlene was put on life support and died two days later, she had already offered a hint as to who her killer might be. She had previously told both her son and her mother that if something happened to her, the culprit was likely her husband — Joe’s stepfather — Mike Warren. It was as good a place as any for investigators to start looking.
Though Mike Warren had an alibi, investigators soon learned that he’d been having an affair with a woman named Sheila Keen. And in the years after Marlene’s murder, Mike and Keen got married.
Yet the case went unsolved for decades.
Inside Michael And Marlene Warren’s Not-So-Happy Marriage
Family PhotoMike and Marlene Warren.
According to a special on Oxygen’s Snapped about the case, Marlene Warren was a “Midwestern girl” who had grown up on her grandfather’s farm. At 20 years old, she was a single mother of two boys: Joe and John. That’s when she met Michael Warren, then 18, and the two quickly fell in love.
A few years later, they were married, and Michael reportedly cared for Joe and John as if they were his own sons.
“That’s the only father I knew,” Joe Ahrens told CBS News’ 48 Hours. “I mean I was really young when my real father and mother separated.”
Ahrens was three years old when his mother married Mike, and their life seemed good at first. They settled into a nice community in Wellington, Florida, where Marlene owned several businesses, and Mike and Marlene operated a business called Bargain Motors, selling and renting used cars.
Family PhotoMike Warren and his stepson Joe Ahrens.
But things weren’t as happy as they might have seemed on the surface. After the sudden death of John in a car accident in 1988, the couple started drifting apart. And by 1990, Marlene had began to suspect that Mike was having an affair. What’s more, she began to fear for her own life.
“She said, ‘if anything does happen to me, your father did it,'” Ahrens recalled to CBS. “I told her no way — he would never do anything like that. She said ‘don’t put it past him.'”
Marlene’s mother, Shirley Twing, said she received the same ominous warning: “[Marlene] says, ‘If anything happens to me, Mike did it.'”
Unfortunately, Marlene Warren was right. Her husband was having an affair, and her life was in danger.
Mike Warren And Sheila Keen’s Deadly Affair
After John’s death, Mike Warren reportedly threw himself into work at Bargain Motors. But it seems that the business wasn’t the only thing that caught his attention. Co-workers at the auto shop were quick to tell investigators that he had been having an affair with an employee named Sheila Keen.
15th Judicial Circuit Court
Sheila Keen in an undated photo.
“It was no secret that he was a player,” former employee Don Carter told Oxygen. “They’d leave the doors right open. There was no hiding it.”
Though Keen was married at the time, she got divorced after falling in love with Mike Warren. According to several of their fellow employees, she became “possessive” of Mike, though most believed that Mike was interested in having only a casual sexual affair with her.
That calculus changed when Marlene Warren was shot and killed.
Palm Beach Sheriff’s OfficeParamedics wheeling Marlene Warren’s body out of her home.
Mike Warren was the obvious first suspect. Not only had Marlene told her son and mother he might do something to her, but Mike also benefited financially from his wife’s death. Everything they owned together was in her name, so when she predeceased him, he acquired 100 percent of those assets. Mike, however, had an alibi. At the time of Marlene’s murder, Mike was in a car with some friends on their way to a horse race.
But investigators soon learned about his relationship with Keen.
“Everybody at the Bargain Motors were reporting that you should look first at Sheila Keen,” assistant state attorney Aleathea McRoberts, who worked on the case, recalled. “And within the next day or so, tips were being called in that you really should investigate Sheila Keen and Michael Warren.”
Keen claimed that she had been looking for repossession vehicles at the time of Marlene Warren’s murder, but she was unable to name any specific locations or times. She — and Mike — also denied having an affair, and Keen said that she did not own a clown costume.
That said, police found a store owner who remembered a woman fitting Keen’s description buying a clown costume a few days before Marlene was killed. Workers at a local supermarket also remembered a woman with long, dark hair buying flowers and balloons like the clown had been carrying. And Ahrens’ description of the killer’s vehicle also led investigators to find the clown’s getaway car. Inside, they found brown hair which seemed to match Keen’s, and orange fibers that looked like they were from a clown’s wig.
Palm Beach Sheriff’s OfficeA bloody rag next to the flowers Marlene Warren received on the day of her murder.
Still, they were missing the smoking gun. Investigators suspected that they knew what had happened, but they couldn’t quite tie all of the evidence together — especially before modern-day advancements in DNA technology.
But Mike Warren and Sheila Keen couldn’t evade the law forever.
Sheila Keen’s Arrest In 2017
Just four months after Marlene Warren’s murder, Mike Warren was arrested — though not in connection with her death. Police instead raided his car lot, where they found evidence of racketeering and odometer fraud, which was enough to put him behind bars for the next eight years. Upon his release in 1997, he decided to start a new life.
Mike Warren remarried and moved to Tennessee with a blonde woman named Debbie. But Debbie wasn’t her real name, and she wasn’t a natural blonde. Mike’s new wife was none other than Sheila Keen.
FacebookMike Warren and Sheila Keen-Warren, who changed her name to “Debbie.”
“Here’s someone whose wife had been murdered and he just married the chief suspect,” said Palm Beach County State Attorney Dave Aronberg. “When you combine the fact that the two of them were in an affair… and then later, they got married, it did seem like mission accomplished.”
In Tennessee, Mike Warren and Sheila Keen opened up a burger restaurant called the Purple Cow, where rumors about their past swirled. Former employees described Keen as “awful aggressive, mean,” and claimed they had even heard rumors that “Debbie killed Mike’s ex-wife.” And “Debbie,” for her part, wasn’t subtle. She even dressed as a clown at the restaurant for Halloween one year.
15th Judicial Circuit CourtSheila Keen Warren in a clown costume for Halloween at her burger shop in Tennessee.
Back in Florida, investigators were still determined to solve Marlene Warren’s murder. In 2014, police received a grant for cold case investigations and were able to re-examine that brown hair they had found in the clown’s getaway car. They had also found a second strand of hair attached to a balloon from the crime scene, and after being sent off for comparison with a hair Keen had provided, it came back as a match.
Sheila Keen Warren was finally arrested for first-degree murder on Sept. 26, 2017 — a full 27 years after Marlene Warren was killed.
The Lingering Aftermath Of Marlene Warren’s Murder
Washington County Sheriff’s OfficeSheila Keen Warren’s mugshot after her 2017 arrest.
After Sheila Keen Warren’s arrest, she was extradited back to Florida, where COVID-era restrictions held up her trial for five years.
Her husband stood by her side, insisting that he and Sheila had nothing to do with Marlene’s murder. Sheila’s defense attorney Greg Rosenfeld also blamed investigators for letting Marlene’s killer — who was not Sheila Keen Warren, he said — get away “because the Palm Beach County Sheriff’s office and the State Attorney’s Office did such a poor job investigating this case.”
Despite this, prosecutors initially sought the death penalty for Sheila, then lowered the bar to life in prison. Then on April 25, 2023, Sheila Keen Warren agreed to a plea deal, which carried a sentence of 12 years in prison. At the time, it was reported that she could wind up leaving prison as early as 2025.
In fact, it happened even earlier.
Washington County Sheriff’s DepartmentSheila Keen Warren following her 2017 arrest.
In November 2024, CNN reported that Sheila Keen Warren had been released from prison just 18 months after entering her guilty plea. Rosenfeld stated that, after spending five years in custody, Sheila only accepted the plea deal because she knew she would be released quickly. Mike Warren echoed that statement.
“My wife did not commit this crime,” he said. “It was difficult to see her plea to a crime she did not commit, but it wasn’t worth the gamble when she was offered a deal that’ll have her home in 16 to 18 months…”
For Joe Ahrens, who struggled with alcoholism and drug addiction after his mother’s death, Sheila’s guilty plea was a relief nonetheless.
“[It] was very emotional because that was the end of something so huge that grew for 33 years of my life,” he said. “Finally [it was over], you know. It was phew.”
Aronberg reacted similarly. At the end of the day, a guilty plea is a guilty plea, and he said: “Sheila Keen-Warren will always be an admitted convicted murderer and will wear that stain for every day for the rest of her life.”
After reading about the tragic death of Marlene Warren, read about Carolyn Warmus, the woman who killed her lover’s wife. Then, read about Greggory Smart, the man murdered by his wife’s underage lover.
