Bishop Francis Kane, the vicar general, said the archdiocese was not trying to cover up or enable the sexual abuse of children by priests, the Chicago Sun-Times reported. He spoke to the news media Wednesday as files on abusive priests were released.
Diocesan officials were told priests who had been evaluated could be returned to the ministry as long as they were under monitoring, Kane said.
"We found out that isn't true," he said. "That was a mistake. We didn't realize the depth of this terrible, terrible sin and crime . . . child sex abuse."
Kane also apologized to those abused by priests and to their families, the Chicago Tribune reported.
More than 6,000 pages of files were released Wednesday to lawyers representing alleged victims of clerical molestation.