The Archdiocese of Philadelphia said Friday it has found "credible evidence" that 35 priests sexually abused children over five decades and relieved several of them of their duties.

About 50 children were victims, diocesan spokeswoman Catherine Rossi said.

Rossi could not say how many of the 35 names had been given to police when the allegations were made. She said the archdiocese followed state law.

The archdiocese will not turn over the names of the priests now because the statute of limitations has expired in all of the cases, she said, adding that most allegations involved one victim.

"We will follow the letter of the law 100 percent, but we are not going to go back and release the names of priests from years ago," Rossi said. "We don't see any good that would come from that, for either the victim or the priest."

She said the fewer than 10 priests had faced "credible" abuse allegations years ago and had been working in administrative jobs since then.

Of the remaining accused priests, four were diagnosed as pedophiles and either left the priesthood or retired. The others were either relieved of their duties, retired, left the priesthood or died, Rossi said.

One priest, the Rev. Michael Swierzy, 53, pleaded guilty in 1998 to one count of corrupting the morals of a minor after a boy came forward in May 1997 with allegations of abuse. The boy is suing Swierzy and the church, Rossi said.

The archdiocese said it reviewed records dating to 1950, prompted by a sex-abuse scandal in Boston, where church leaders admitted they knew about abuse allegations against a priest but did little to stop him.

That scandal prompted Philadelphia church leaders to relieve several priests in administrative jobs of their duties, Rossi said.

"The tragic situation in Boston gives the church great concern and great pause," Rossi said. "Sadly, there is a ripple effect."

Some of the Philadelphia priests involved were shuttled from parish to parish – a practice stopped in the early 1980s, Rossi said. She did not know how many priests were treated in that manner.

In the past, a priest facing a credible allegation of abuse was placed in a "limited ministry" – essentially a closely supervised administrative position that did not involve contact with children, Rossi said.

There are about 800 diocesan priests in the archdiocese, which serves about 1.5 million Catholics. Since 1950, about 2,100 priests have served the archdiocese.

There have been no allegations against any diocesan priest in the last three years, Rossi said.

During the 1990s, the archdiocese paid about $200,000 to settle a handful of abuse cases.