Behind the locked doors of a hospital chapel on one of the most sacred days in the Catholic calendar, Sister Margaret Ann Pahl was brutally murdered by her colleague, the Rev. Gerald Robinson, an Ohio prosecutor told jurors Friday.

However, as Robinson's trial began for the nun's gruesome death on April 5, 1980, Lucas County prosecutor Dean Mandros told the panel in his opening statement that he would not be presenting them with a motive.

Instead, Mandros promised jurors that a letter opener belonging to Robinson and eyewitness testimony would link the 68-year-old priest to the altar where Pahl's partially nude body was found stabbed and strangled in the sacristy of the Mercy Hospital chapel in Toledo.

"You will learn how the defendant and the victim were together in the sacristy of that chapel and how one of them died a horrible death," Mandros said.

With the defendant wearing his priest's collar at the defense table, Mandros gave a brief but chilling overview of the manner in which a fellow nun found Pahl around 8 a.m. the day before Easter — and the day before the victim's 72^nd birthday.

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"She was working on the altar and it was in the sacristy of that chapel that someone took her by the neck and choked her so hard that two bones broke on the side of her neck," Mandros said. "Blood vessels in her eyes burst as she was choked to the verge of death." (VIDEO)

Pahl's assailant then laid her body on the floor and covered it with a cloth from the altar before stabbing her nine times over her heart in the shape of an upside-down cross, Mandros said. The killer then removed the cloth and stabbed her at least 22 more times before raising her skirt and rolling down her undergarments.

There was no evidence of sexual assault, Mandros said, and authorities quickly concluded that the murder was the work of someone the victim knew.

"Strangers don't typically have that type of energy, emotional anger, to stab someone 35 times," Mandros said.

But a lawyer for Robinson likened the state's case to an incomplete jigsaw puzzle and said the evidence against his client was just as scarce now as it was back in 1980.

"In 1980, when the original investigation began, you will find from witnesses that there were important inconsistencies and discrepancies," said defense attorney Alan Konop. "You'll also find some old witnesses from 1980 that gave a new spin in 2003, that added some information 23 or 24 years after the event." (VIDEO)

Konop told the panel that Robinson, a longtime suspect in the case, was arrested before any extra reports or testing were done. Even after Pahl's body was exhumed for DNA testing, Konop said authorities were still unable to link Robinson to the murder.

"There's an indictment and arrest first, and then the questions are asked," he said. "This is all being done after the humiliation and degradation of an arrest of Father Robinson."

After openings, the jury was set to view the crime scene and the quarters where Robinson lived in Mercy Hospital. Testimony is set to begin Monday.

The trial is being streamed live on Court TV Extra.