A long-dead man with a history of sexual violence against young girls has been identified as the killer of 9-year-old Carol Ann Dougherty in 1962, officials in Bucks County, Pennsylvania, said Wednesday.

William Schrader, who died in 2002, is believed to have murdered Dougherty in October 1962 at St. Mark's Roman Catholic Church in Bristol Borough, District Attorney Jennifer Schorn announced. Schrader spent time in prison for other crimes.

About one year after sending DNA to a Texas lab in an effort to solve a 63-year-old cold case, officials made the announcement related to the murder of 9-year-old Carol Ann Dougherty in Bucks County, Pennsylvania.

Dougherty had been sexually assaulted and was found lying under a stained glass window in the choir loft, Schorn said.

"You can't even imagine the challenges that a case like this poses," Schorn said during a press conference about the case.

Carol Ann's sister Kay, who was 3 years old when it happened, said she wondered whether this day would ever come — and she's grateful it finally did. 

"After so many decades of unknowing, this finding finally brings closure and a truth to a wound that never healed," she said. "Though nothing can bring Carol back, we can finally let her rest in peace, knowing that her story has been told, her truth revealed and her memory honored."

The fifth-grader had stopped in the church to say a prayer, as nuns instructed her to do, "CBS Saturday Morning" reported. Newspapers ran photographs of a gurney transporting Dougherty's body down the steps of the church, covered in a white sheet. The news shocked the small community outside Philadelphia and stayed in local memory for generations without answers.

Schrader lived with relatives on Lincoln Avenue near the church, according to Schorn. He was not initially identified as a suspect until more than two months after the murder when a citizen called with a tip that Schrader was acting strangely — and had cut through their backyard. Other witnesses described seeing a man with a description matching Schrader's, looking suspicious — possibly like he had just killed someone, Schorn said.

Schrader later moved to Louisiana, and family members testified to Bucks County authorities that he had a history of sexually abusing relatives. Schorn said his past history of sexual abuse was unlike anything she had ever seen in her career as a prosecutor.

Schrader also once admitted to a relative in Louisiana that he had raped a little girl in a Catholic church back in Pennsylvania before moving to the South. He told the relative that he killed the girl out of fear she would tell others what he did — and then fled town.

That relative relayed the story to Louisiana law enforcement, but it never made it to investigators in Pennsylvania. Five years after Schrader's death in 2002, the relative came forward and provided a statement "emphatically" relaying that story, Schorn said. 

Investigators announced last year that DNA tests would move forward, trying to find a link in the crime scene evidence believed to be from the killer to relatives of the main suspects in the case.

CBS Saturday Morning identified those suspects as the Rev. Joseph Sabadish, who died in 1999 and had been accused of molestation. He was never charged with connections to Dougherty.

After announcing that the DNA tests — conducted by Othram labs in The Woodlands, Texas — were being arranged, Schorn warned that the tests may prove inconclusive.

Bucks County Courier Times journalist JD Mullane reported that the evidence sat for decades in an attic in a municipal building, suffering from years of temperature changes, and is very degraded. However, DNA testing technology has improved greatly in recent years, leaving a chance that there could be a usable sample.

A different lab in California, Astrea, was able to identify murdered 4-year-old Carl Bryant, who was found dead in Fairfax County, Virginia, in 1972. Bryant's identity was unknown for over 50 years until Astrea established a DNA profile with what a detective described as roughly "two millimeters of hair."

Dougherty's case gained renewed attention from "The Coldest Murder," a podcast by local sports radio host and Bristol native Mike Missanelli that examined the case over 14 episodes. Missanelli was seven years old at the time of the murder and his uncle, Vincent Faragalli, was the police chief at the time.

Missanelli told CBS' Dana Jacobson his uncle kept Carol Ann's picture on his bureau — never to forget the case.