COLUMBUS, Ohio (AP) — A death row inmate who killed himself was found hanging in his cell, according to a report released by the Ohio State Highway Patrol Wednesday.

Condemned killer Patrick Leonard was pronounced dead at Adena Hospital in Chillicothe on Sunday, the report said.

The Ross County coroner’s office said the preliminary cause of death was strangulation. Neither agency said what Leonard used to hang himself with. The state prisons department said it wouldn’t release any details until the patrol’s full report was complete.

Leonard was sentenced to death for the 2000 killing of his ex-girlfriend, 23-year-old Dawn Flick, in Hamilton County. Court records say the 47-year-old Leonard was angry at Flick for ending their relationship and refusing to reconcile.

He was unusual among death row inmates in that he didn’t have a criminal record before the killing.

Leonard didn’t have a scheduled execution date.

Hamilton County Prosecutor Joe Deters, a critic of execution delays, said: “Finally someone on death row has died.”

Many condemned inmates have been on death row for two decades or more. On Friday, the Ohio Parole Board will make its recommendation for or against mercy for Raymond Tibbetts, who was sentenced in 1998 to death.

Executions in Ohio have been on hold since January 2014. A federal appeals court in Cincinnati is weighing a lawsuit challenging the constitutionality of the state’s new three-drug method.

State attorneys say they’ve provided plenty of evidence that the first drug, the sedative midazolam, will put inmates into a deep state of unconsciousness.

Lawyers for death row inmates disagree, saying the drug creates a substantial risk of harm to inmates because it won’t render them fully unconscious.

The court heard arguments Tuesday. Ohio hopes to execute killer Ronald Phillips on May 10. Phillips has been on death row since 1993.