Michigan law enforcement officials made their first arrests in a statewide investigation into Roman Catholic clergy sexual abuse, the state’s attorney general announced on Friday.

Five former Catholic priests have been charged with criminal sexual conduct, Attorney General Dana Nessel said at a news conference. But hundreds, or even thousands, of alleged victims could still remain across the state, she said.

“This is just the tip of the iceberg,” she said. “We anticipate many more charges and arrests.”

The charges were the latest effort by law enforcement nationwide to hold Catholic officials accountable for sexual abuse in the church. Since Thursday, four of the former priests were arrested in Arizona, California, Florida and Michigan. The fifth faces possible extradition from India.

Michigan began its extensive investigation into clergy abuse last August, after an explosive grand jury report in Pennsylvania alleged that bishops and other church leaders covered up widespread child sexual abuse over several decades. That investigation has so far resulted in two convictions, and roughly 1,700 tips to a dedicated clergy abuse hotline. A district attorney in Pennsylvania recently charged a third former priest.