Updated

A former elementary school music teacher will spend the rest of his life in prison after pleading guilty to fatally shooting his ex-wife -- also a music teacher -- while she played the organ during a church service in northern Pennsylvania last year.

Gregory Eldred, 53, of Coudersport, avoided a possible death penalty by pleading guilty to first-degree murder and will instead receive a mandatory life term without parole when he returns for sentencing by a Potter County judge on Tuesday.

Eldred acknowledging that he gunned down 53-year-old Darlene Sitler at the First United Presbyterian Church of Coudersport on Dec. 2. The church is about 140 miles northeast of Pittsburgh.

Until the shooting, Eldred had been an elementary school music teacher in the Coudersport Area School District since 1986 and played clarinet for the Southern Tier Symphony Orchestra in nearby Allegany, N.Y. His ex-wife had taught music at the Northern Potter Children's School in a neighboring district for 30 years.

After the facts of his crimes were recited in court, Potter County Judge Stephen Minor asked Eldred, "Are those facts accurate? Did you do that?"

"Yes, your honor," Eldred responded, according to The Bradford Era.

The couple had been divorced since August 2010, according to court records. Investigators have never detailed the precise motive for the shooting though District Attorney Andy Watson provided a partial explanation during Wednesday's plea hearing, saying Eldred killed his wife over "information she possessed."

The prosecutor didn't detail that information and didn't immediately return a call seeking additional comment Thursday.

Eldred's attorney, William Hebe, also didn't return a call for comment and has previously declined to discuss details of the case.

According to the state police, Eldred shot his ex-wife while she sat at the organ during church service and, after leaving briefly, returned and shot her again to ensure she was dead. Sitler, the choir director, was shot about 20 minutes into the 11 a.m. service.

Pastor Evon Lloyd told police that Eldred entered the church wearing a hooded jacket and "leveled a gun at the victim and shot," according to the criminal complaint. Sitler fell into the organ pit before Eldred left the building and put a handgun on the hood of his vehicle while those inside called 911 and aided Sitler.

Another witness, Leslie Rolfe, said Eldred picked up the gun about five minutes later, while Rolfe tried to hold the church doors shut but couldn't. Rolfe and his wife tried to persuade Eldred to drop his gun, but he threatened to shoot them and the pastor, saying "I want to finish this," the complaint said.

Eldred then walked toward his ex-wife saying, "I got to see her. I got to see if she's dead," before firing two more shots, the complaint said.

Police said nobody else was hurt, though Eldred's gun went off once when Rolfe and other members of the congregation struggled to subdue him.

State police arrived minutes later and took Eldred into custody without incident.