A grand jury met Friday to consider the charge against the Rev. Gerald Robinson, but its decision was not announced until Monday.
Robinson was arrested April 23 in the strangling and stabbing of Sister Margaret Ann Pahl, 71, during Easter weekend in 1980. He was long a suspect in her death.
The nun's body was discovered in a chapel at Mercy Hospital, covered by an altar cloth. Investigators have described it as "ritualistic" slaying that has the Toledo Diocese looking into claims of satanic sex abuse by priests.
Robinson was released from jail Monday after supporters put together enough property to post a $400,000 property bond to cover his $200,000 bail. He said nothing before getting into a sport utility vehicle that was waiting for him.
Robinson's attorney, Alan Konop, said his client will plead not guilty. Regardless of the outcome of the trial, Robinson will not be subject to the death penalty because it was not in effect in Ohio at the time of the killing.
Detectives have said some type of ceremony appears to have been a part of the killing. Police also say they believe Robinson acted alone.
Robinson was arrested after investigators analyzed blood patterns and concluded that the murder weapon was in his "control." They have not identified the weapon or who owned it.
Investigators began to review the slaying after a woman contacted them alleging she was physically and sexually abused as a child by several priests, including Robinson.
Three other people came forward after Robinson's arrest claiming they were abused by priests in rituals years ago.
Authorities reopened the murder case in December based on information in a letter sent to prosecutors, but they would not say who sent the letter or what it contained.