'Culture of Silence: Abetted abuse of at least 547 German choir boys'

The estimate of the number of children abused was far greater than a previous figure, 231, that the lawyer gave last year. The choir — the Regensburg Domspatzen, literally the Cathedral Sparrows — dates to the 10th century and continues to perform at Sunday Mass in Regensburg's 16th-century Gothic cathedral. The choir's music director from 1964 to 1994 was the Rev. Georg Ratzinger, whose younger brother, Joseph Ratzinger, reigned as Pope Benedict XVI from 2005 to 2013.

Father Ratzinger, now 93, has apologized for slapping boys during his tenure, and said he stopped administering corporal punishment when the church banned it in 1980. He has denied awareness of sexual abuse taking place, and the new investigation does not implicate him in it.

The abuse came to light in 2010. Over the past two years, Weber and a team of colleagues conducted interviews with victims and other former pupils and scanned archives from 1945 to 1992.

Over all, Weber evaluated 616 reports of abuse; he deemed fewer than a dozen not at all plausible. Others, Weber determined to be questionable, meaning that the abuse could not be ruled out.

In the remaining cases, 547 in total, the reports of abuse were deemed plausible, based on interviews or other corroborating evidence. Of those cases, 67 are believed to have involved sexual abuse. The others involved various forms of corporal punishment, including ear-twisting and beatings with a cane.

As in other institutions in which longstanding patterns of abuse have come to light, a combination of shame, secrecy and impunity contributed to the abuses at the music school in Regensburg, which is about 70 miles northeast of Munich, in southeastern Germany. The abuse remained taboo, discussed only among some of the victims, who felt ostracized by their fellow alumni.

The most severe abuse took place among primary-school students in the 1960s and '70s, mostly boys 9 to 11 living away from home. "In the three areas of school, choir, musical education and boarding school, many people actively took part in the abuse," Mr. Weber said. The inquiry found the abuse was perpetrated by 49 people, most of them priests, who served as teachers and administrators and performed other jobs in the school.

In the report, dozens of former students described their primary-school years as a "prison," "hell" or "concentration camp," he said.

"Many described this time as the darkest period of their lives, dominated by violence, fear and helplessness," Weber said.

Survivors expressed relief at the release of the report, but one of them, Udo Kaiser, said it could not restore their stolen childhoods. "It has been documented," Kaiser said in a telephone interview from his home in Munich. "Everything I have been saying for the past 30 years, when no one believed me, everything I have been fighting for the past seven years is now public." AGENCIES