Nearly 50 years after a northern Kentucky teenager was found slain in a rural roadside ditch, investigators say they used advanced DNA testing to identify a suspect.

The Boone County Sheriff’s Office began working the case of 16-year-old Carol Sue Klaber in 2017 after establishing a new cold case unit. Investigators said during a news conference on Wednesday that they believe former Park Hills resident Thomas W. Dunaway killed Klaber. Dunaway had a criminal history and died in 1990 at the age of 33, officials said.

Klaber’s body was found in Walton on June 5, 1976, and an investigation at the time found that she died of blunt force trauma with evidence of strangulation and sexual assault. Kentucky State Police worked the case for nearly a decade before it went cold.

After taking over the case, detectives ruled out two suspects and then partnered with Othram Inc. of Houston, Texas, to see if advanced forensic DNA testing could help identify a suspect. Othram scientists built a comprehensive DNA profile and used forensic genetic genealogy that produced leads and helped the Boone County Sheriff’s Office identify Dunaway, officials said.

Along with the DNA evidence, Dunaway resembled a sketch that had been done of the suspect in Klaber’s case, he lived in the area where Klaber was last seen and he drove a vehicle similar to the car that Klaber was last seen getting into.

The sheriff’s office asked prosecutors to indict Dunaway posthumously, but the office declined. However, prosecutors said they would seek charges against Dunaway if he was still alive.