(CNN) -- Facing lethal injection in a matter of days, Ohio murderer Billy Slagle apparently hanged himself in his prison cell early Sunday, state corrections officials said.
Slagle was discovered in his cell at the Chillicothe Correctional Institution just after 5 a.m. Sunday and pronounced dead about an hour later, said Jo Ellen Smith, a spokeswoman for the state Department of Rehabilitation and Corrections. He was to have been put to death Tuesday, Smith said.
Slagle had been on death row since 1988, convicted of murder after stabbing a neighbor to death in her Cleveland home. Ohio's parole board voted 6-4 against his petition for clemency in June, and Gov. John Kasich denied his request on July 24.
The refusal came despite the rare support for a commutation from Cuyahoga County Prosecutor Timothy McGinty, whose office recommended Slagle's sentence be reduced to life in prison without parole.
Slagle was 18 and already had a long history of drug and alcohol abuse when arrested in the killing of Mari Anne Pope, who was stabbed 17 times with scissors while her children were in the home, according to court records. His family had a long history of alcoholism and domestic abuse, and he spent his teenage years "largely unsupervised by any adult," his attorneys argued in seeking clemency.
McGinty said in July that there was "no doubt of Slagle's guilt," but jurors at the time didn't have the option to consider a sentence of life in prison without parole. If the case were brought today, McGinty said, prosecutors weren't likely to seek the death penalty.
Slagle was in solitary confinement, Smith said. Prison officials have launched an investigation into how he died, she said, and no further details had been released Sunday afternoon.
An autopsy was scheduled for Monday, Mike Ratliff, chief investigator for the Ross County Coroner's Office, told CNN.