She disappeared in 1989. Her body was never found. The case has been unsolved for 28 years.
But detectives think they know who killed her.
Miami Township's police chief and lieutenant in charge of investigations sat down with Spencer’s family Monday. Police told WCPO they are dedicated to spending months reviewing every piece of evidence that could finally bring justice for Spencer.
Karen was the youngest of Diane and Richard Spencer’s seven children. Through the years they have shared pictures and memories of their missing daughter.
“She used to get angry and she'd say, ‘I'm going to run away from home,’” said Diane Spencer, Karen’s stepmother. “I’d say, ‘OK, but don't leave the yard.’ She'd say ‘OK’ and out the door she'd go and sit down on the curb.”
But that strong will cost Karen her life.
“The only thing she did was something stupid - stupid, stupid thing,” Diane said in deepest regret.
Karen got into an argument with her sister-in-law while they were driving on I-275 in Miami Township on a December night in 1989.
She got out of the car. Her sister-in law drove off. As she did, she saw Karen talking with a man in a red Datsun.
Retired Miami Township Det. Bill Paul says he interviewed that driver numerous times and Paul is convinced that man killed Karen, as was the FBI after reviewing the case.
“I felt absolutely 100% positive I got the right person. They said it's just a matter of finding the right button to push,” Paul said.
Paul says the suspect was a young man in his early 20s just out of the military. The man admitted he spoke with Karen on the interstate.
And Paul says the red car he was driving that night vanished right when Karen did.
Lt. Greg Jenkins confirms he will now take on the case full-time, hoping he can finally give closure to Karen's family.
WCPO asked Jenkins if he knows where the suspect is. “Yes, we know where the primary suspect is right now,” Jenkins said.
Authorities ask anyone with information about Karen Spencer's case to call 513-248-3721.