The grand jury also found that the Philadelphia Archdiocese kept 10 accused child molesters in active ministry even after June 2002, when all the U.S. bishops promised in Dallas to remove any priest who had ever faced a credible allegation of abuse. Two accused priests are still in ministry in Philadelphia, prosecutors said.

The scathing, 418-page report vents the grand jury's frustration that it was unable to indict anybody. It says there is clear evidence in church files that Krol, who died in 1996, and Bevilacqua, who retired two years ago, "enabled and excused" abuse by transferring accused priests from parish to parish without warning parishioners or informing police.

Among the priests they protected, the grand jury said, was one who raped an 11-year-old girl and then took her in for an abortion, and another who groped a teenage girl while she lay immobilized in traction in a hospital bed after a car accident.

"But the biggest crime of all is this: it worked," the report said. "The abuser priests, by choosing children as targets and trafficking on their trust, were able to prevent or delay reports of their sexual assaults, to the point where applicable statutes of limitations expired. And Archdiocese officials, by burying those reports they did receive and covering up the conduct, similarly managed to outlast any statutes of limitation. . . . We surely would have charged them if we could have done so."

Cardinal Justin Rigali, who succeeded Bevilacqua, detailed at a news conference the steps the church has taken to protect minors. "I acknowledge the pain and suffering of the victims of clergy sex abuse," he said. "To them, I repeat my heartfelt and sincere apologies."

But the archdiocese vigorously rejected the grand jury's assertion of a coverup. While acknowledging the "abhorrent behavior of certain of its priests," it said in a 69-page rebuttal that the report is "nothing more than an attempt to convict in the court of public opinion those whom it does not indict in a court of law." A spokesman for the archdiocese said Bevilacqua was "deferring to Cardinal Rigali to respond."

Prosecutors led by Philadelphia District Attorney Lynne Abraham said the archdiocese turned over 45,000 documents but only under subpoena. "The manner in which they responded to the report does not create confidence that there has been a significant change in their attitude toward the underlying problem," said Ronald Eisenberg, a deputy district attorney.

Eisenberg said prosecutors also believe that the Philadelphia Archdiocese has significantly underreported the number of its sex abuse cases to the public and to the U.S. Conference of Catholic Bishops.

A 2004 nationwide study commissioned by the bishops' conference found credible allegations against 4,392 priests, or about 4 percent of all those active in the United States since 1950. Sex abuse victims' groups have doubted the accuracy of the study, because it was based on self-reporting by all 195 U.S. dioceses.

The grand jury report says the Philadelphia Archdiocese knew of serious allegations, often involving multiple cases of rape, against at least 63 priests, and probably more. Rigali has reported to the bishops' conference and on the diocese's Web site that 44 Philadelphia priests were credibly accused of abuse and that all of them have been removed from ministry.

Grand juries in Boston; Manchester, N.H.; Long Island, N.Y., and other cities have issued similar reports on sex abuse in the church. Terry McKiernan, co-director of BishopAccountability.org, a Web-based group in Massachusetts, said the Philadelphia report was the most thorough and hard-hitting so far, accusing Krol and Bevilacqua of behaving in much the same way that Cardinal Bernard F. Law did in Boston.

"You think you can't be shocked anymore, and along comes something like this," McKiernan said.