You might have heard the name Mike Warren. Maybe you’re looking for real estate advice, or perhaps you’ve seen those Seth Godin marketing books about being "remarkable" like a purple cow. But if you’re looking into Mike Warren Purple Cow Tennessee, you aren't stumbling onto a business seminar. You're walking into one of the most bizarre true crime stories in American history.
It’s a tale that involves a drive-thru burger joint, a decades-old cold case, and a killer clown. Honestly, it sounds like a bad movie script. But in Kingsport, Tennessee, it was very real.
What Really Happened with Mike Warren and the Purple Cow?
Back in the 1990s, the Purple Cow was just a quirky, popular restaurant at 1648 East Stone Drive in Kingsport. It was famous for having over 100 milkshake flavors and some pretty solid burgers. The owners? Mike Warren and his wife, Debbie.
People liked them. They were hardworking. They seemed like a normal couple who moved to Tennessee to start fresh. Mike was a car guy, and Debbie ran the shop. But "Debbie" wasn't actually Debbie.
Her real name was Sheila Keen. And Mike wasn't just some guy from Florida; he was at the center of a murder investigation that had gone cold for nearly thirty years.
The 1990 "Killer Clown" Murder
To understand the Tennessee connection, you have to go back to May 26, 1990, in Wellington, Florida. Mike Warren’s then-wife, Marlene Warren, was at home when a white Chrysler LeBaron pulled into the driveway.
A person dressed as a clown—complete with an orange wig, a red nose, and a painted-on smile—walked up to the front door. The clown was carrying a bouquet of flowers and two balloons. One said "You're the Greatest."
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When Marlene opened the door, the clown handed her the items, pulled out a gun, and shot her in the face.
The clown walked back to the car and drove away. Marlene died two days later.
Why Mike Warren Moved to Tennessee
Investigators immediately looked at Mike. He had a mistress—Sheila Keen—who worked at his used car lot, Bargain Motors. Rumors were flying that the two were having an affair. But Mike had an alibi; he was on his way to a horse race with friends when the shooting happened.
Sheila had an alibi too. Well, sort of. She was "out looking for cars."
Despite finding a clown costume in Sheila's apartment and witnesses placing her at a costume shop, the evidence was circumstantial. The case stalled. Mike eventually went to prison for racketing and odometer fraud—totally unrelated to the murder.
When he got out in 1997, he and Sheila disappeared. They moved to the mountains. They landed in Tennessee.
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The Life of the Purple Cow Tennessee
For years, Mike and Sheila (now "Debbie") ran the Purple Cow Tennessee restaurant. It was a local staple. Mike handled the business side, and Sheila was the face of the place.
It's wild to think about. People were buying "Steak Bombs" and "Purple Milkshakes" from a woman who was the prime suspect in a legendary Florida hit.
The most chilling part? Employees later told detectives that Sheila actually dressed up as a clown for Halloween at the restaurant. She didn't hide. She leaned into it. Some workers said there were always whispers that "Debbie" had killed Mike’s ex-wife, but it was treated like a local urban legend rather than a lead.
The 2017 Arrest and the End of the Secret
The law eventually caught up. In 2017, advances in DNA technology allowed investigators to re-examine hair samples found in the clown’s getaway car. The DNA matched Sheila Keen-Warren.
Police didn't find her in Florida. They found her across the border from Kingsport in Abingdon, Virginia, where she and Mike were living. The "Purple Cow" owners were finally exposed.
Sheila was extradited to Florida. Mike Warren was never charged in connection with Marlene's death, though many still believe he was the mastermind behind the whole thing.
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What Most People Get Wrong About This Case
There's a lot of noise online, especially since Sheila Keen-Warren actually took a plea deal in 2023. Here’s the reality of where things stand:
- She isn't in prison anymore. Despite the "Killer Clown" label, Sheila pleaded guilty to second-degree murder and was sentenced to 12 years. Because she had already spent seven years in jail awaiting trial and Florida law at the time of the crime allowed for massive "gain time" credits, she was released in late 2024.
- Mike Warren is still a free man. He has consistently denied involvement. Even though the motive seemed to be the couple's desire to be together and collect on Marlene's life insurance and properties (worth over $1 million), prosecutors couldn't pin the planning on him.
- The Purple Cow is gone. The restaurant that served as their cover for decades eventually closed and was replaced. The quirky statues of purple cows are a memory, replaced by the grim history of the owners.
Takeaways and Next Steps
The story of the Mike Warren Purple Cow Tennessee connection is a reminder that truth is often stranger than fiction. If you're looking into this for business reasons—perhaps confused by the "Purple Cow" marketing term—the takeaway is simple: remarkability is great for business, but you can't outrun a paper trail (or a DNA trail).
If you’re interested in the legal or investigative side of this story, here is what you can do to dig deeper:
- Review the 48 Hours Special: CBS covered this case extensively, including interviews with the employees at the Tennessee restaurant.
- Search Court Records: Look for the 15th Judicial Circuit Court records in Palm Beach County for the full details of Sheila's 2023 plea deal.
- Visit Kingsport History: Local archives in the Kingsport Times-News offer a look at how the community reacted when their favorite burger joint owners were arrested for a cold-case murder.
The Purple Cow might be closed, but the "Killer Clown" case remains one of the most studied examples of how forensic science can bridge a 30-year gap. Just remember: sometimes a burger is just a burger, but sometimes, the person flipping it has a trunk full of secrets.
To get the full picture of the forensic evidence used to close this case, you can look up the "Marlene Warren DNA Hair Analysis" reports from the 2017 grand jury indictment.