It had all the hallmarks of a carjacking and kidnapping.
On September 27, 1996, a car was found on the side of I-72 in central Illinois. The vehicle’s engine was still running, the headlights were on, the driver’s side door was open, and no one was in it.
Investigators learned that the Pontiac Bonneville was registered to David Swann, who told authorities that his girlfriend, Karyn Slover, 23, was driving his car that evening because hers needed repairs.
Karyn left work in the advertising sales department of the Decatur Herald & Review to pick up her 3-year-old son, Kolten. He was being cared for at the home of Michael Slover Sr. and his wife, Jeannette, parents of Karyn's ex-husband, Michael Slover Jr.
Karyn's former in-laws told authorities that she never arrived that evening and didn’t call them to check in, according to “One Deadly Mistake,” airing Saturdays at 7/6c on Oxygen. Her purse was still in the abandoned car, which raised concern. A missing persons case was opened.
A forensics team examined the car but found no fingerprints or other evidence aside from a half-eaten candy bar, fast-food packages, and, significantly, cinders on the driver’s seat floor mats. Decatur Police Department Detective Mike Beck observed that I-72 was a concrete roadway. Swann told officials that the cinders had not been in the car earlier that day.
Then, three days after Karyn's disappearance, a boater on nearby Lake Shelbyville found a plastic bag containing a human head, according to Moultrie Sheriff’s Office Sgt. Jeff Thomas.
It was a shocking discovery, particularly for community-minded central Illinois. “I was kind of dumbfounded,” said Thomas. “I couldn't believe there actually was a head in this bag.”
A thorough search of the area by police found more plastic bags filled with other body parts. Using dental records, investigators confirmed the remains as Karyn's.
The missing persons case became a homicide. The cause of death was determined to be multiple gunshots to the head — once in the front and six times in the back. Thomas characterized the homicide as “overkill,” which “showed rage” toward the victim and suggested that the murderer knew Karyn Slover.
Karyn had been dismembered, possibly with a power tool, while fully clothed. Plastic bags containing her remains also contained cinders as well as pieces of concrete presumably used to weigh the bags down and submerge them in the lake.
The unthinkable murder sent the community reeling, including the victim’s coworkers at the Herald & Review, where an editor shared the terrible news with staff. “It’s bad. It’s real bad. They have her head,” he said. “It’s at the crime lab.”
Detectives began the investigation by looking at people closest to Karyn. Officials learned that her ex-husband, Michael Slover Jr., had been verbally and physically abusive. However, he worked several jobs and had an airtight alibi for the window of time when his ex-wife went missing and the car she was driving was found.
Swann, meanwhile, played up the role of the victim’s boyfriend to get attention, according to officials. Swann’s rap sheet, which included assault and impersonating law enforcement, compelled investigators to dig deeper into this person of interest. In addition, interviewees told authorities that they’d seen Swann butchering a deer with a chainsaw.
Despite the various red flags, Swann’s alibi of being at a friend’s wedding rehearsal dinner as well as the bank all checked out. The investigation then pivoted to Karyn Slover’s in-laws.
There was bad blood between Karyn and Jeannette, who considered little Kolten to be her child — so much so the divorce agreement between Michael Slover Jr. and Karyn stipulated that Jeannette be the boy’s babysitter, the Herald and Review reported in 2020.
Michael and Jeannette were brought in for questioning and their account of the evening Karyn went missing didn’t hold up. They’d told police that they’d called Karyn when she didn’t arrive to pick up Kolten, but phone records revealed that no such call had been made.
Authorities also learned from a friend that Karyn aspired to be a model and had been offered a dream-come-true job opportunity in another state.
Investigators theorized that Karyn’s plans to leave Decatur with her son may have led her in-laws to take drastic, deadly action.
Michael and Jeannette Slover’s phone records showed a flurry of calls to their son on the evening of September 27. When detectives went to speak to the Slovers, they realized that the parking lot of their business, Miracle Motors, was covered with cinders.
Investigators compared cinders from the car lot to the ones found inside Swann’s car but the analysis came back inconclusive. The investigation stalled. Despite strong suspicions, no arrests could be made.
“It was going to take something special to move it forward,” said Jay Scott, Assistant State Attorney for Macon County.
Two years later, the case crossed the desk of Michael Mannix, an Illinois State Police Special Agent. He believed that the evidence was too strong to let the investigation stay cold, according to “One Deadly Mistake."
Investigators painstakingly spent four months sifting through the Miracle Motors parking lot material. It was like looking for a needle in a haystack, but the search turned up buttons and rivets matching ones from the clothing Karyn Slover was wearing when she was killed and dismembered. “Leaving the buttons and rivets behind was the one critical mistake,” according to investigators.
Investigators now had enough evidence to arrest Michael Slover, his wife, Jeannette, and their son, Michael, on January 27, 2000.
On May 18, 2002, all three were found guilty. Michael Sr. and Michael Jr. were sentenced to 65 years in prison, while Jeannette was sentenced to 60 years.
The Slovers have maintained their innocence.
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