More than 4,800 individuals may have been victims of child sex abuse in the Portuguese Catholic Church and 512 alleged victims have already come forward to speak out, an expert panel looking into historic abuse in the church said Monday.

Senior Portuguese church officials had previously claimed that only a handful of cases had occurred.

Senior clergymen sat in the front row of the auditorium where panel members read out some of the harrowing accounts of alleged abuse included in their final report. There were vivid and shocking descriptions.

The head of the Portuguese Bishops Conference, Bishop José Ornelas, said church authorities would study the panel’s 500-page report before giving an official response.

“We have seen and heard things we cannot ignore,” he told reporters. “It’s a dramatic set of circumstances. It won’t be easy to get over it.”

The Independent Committee for the Study of Child Abuse in the…