TOLEDO, OHIO ? A priest was convicted Thursday of murder in the slaying of a nun who was found stabbed 26 years ago in a hospital chapel, her forehead “anointed” with a smudge of blood, her wounds forming an upside-down cross on her chest.

The Rev. Gerald Robinson, 68, was immediately sentenced to the mandatory term of 15 years to life in prison and led away in handcuffs after a trial in which forensic experts matched the victim’s wounds to a distinctive, sword-shaped letter opener found in the priest’s room.

The jury took six hours to reach a verdict. Robinson’s friends and family gasped when it was read. The Roman Catholic priest showed no reaction.

Robinson, who had worked closely with Sister Margaret Ann Pahl as the hospital chaplain and presided at her funeral Mass, was a suspect early on but was not charged until two years ago. Prosecutors took a closer look at the slaying after he was anonymously accused of molestation. Those allegations have not been substantiated.

Prosecutors suggested that Robinson’s relationship with the nun was strained and had finally reached a breaking point. According to testimony, Pahl was a strict taskmaster as the caretaker of the chapel and was upset about Good Friday worship services being shortened.

Pahl, 71, was killed while preparing the Mercy Hospital chapel for Easter services on April 5, 1980. She was choked and then stabbed 31 times, the blade plunged repeatedly through an altar cloth that was left over her body in what prosecutors said looked like a ritual slaying.