SOUTH BEND, Ind. (AP) — An autopsy has determined that a man who died in jail in March after pleading guilty to murder in the 1988 beating death of a pregnant Indiana woman died of cancer.

St. Joseph County Deputy Coroner Mike Samp gave an update to the South Bend Tribune on the investigation into 78-year-old George Kearney’s death at the St. Joseph County Jail.

Kearney died before a scheduled sentencing hearing in March. Prosecutors at the time said Kearney was terminally ill. Shortly after his death a judge accepted Kearney’s plea and convicted him.

Kearney admitted killing 28-year-old Miriam Rice. She was abducted June 24, 1988, while walking her dog in a park. Kearney’s former girlfriend, 56-year-old Barbara Brewster, also was charged with murder and is awaiting trial.