By Steve Beck, Matt Rivers, Tony Hanson, and Mark Abrams

PHILADELPHIA (CBS) — A former Philadelphia priest has been charged with sexually assaulting an altar boy over a period of four years.

READ MORE: CBS3 Mysteries: Don Ly's Children Continue To Search For Answers After Father's American Dream Ended In Deadly Stabbing In South Philadelphia

Rev. Robert L. Brennan, 75, is facing charges of rape, involuntary deviate sexual intercourse and aggravated indecent assault.

Brennan was arrested Wednesday in Maryland and remains in custody.

Philadelphia District Attorney Seth Williams announced the charges during a news conference Thursday.

Williams said the alleged assaults began in 1998 when the victim was 11 years old and ended in 2001 when the victim was 14.

The victim, Williams said, reported the alleged assault to the Archdiocese of Philadelphia in January of this year. Williams said the archdiocese contacted authorities the same day.

READ MORE: Camden County Businesses, Officials Worry As Heavy Rains, Flooding Become More Common

Williams said the alleged assaults occurred when Brennan was an assistant pastor at Resurrection of Our Lord Church in Northeast Philadelphia.  According to Williams, some of the assaults happened on church grounds, in Brennan’s bedroom, and at a movie theatre.

Brennan’s name appeared several times in the 2005 grand jury report regarding sex abuse by priests in the Philadelphia archdiocese.

“During the tenure of Cardinal Anthony Bevilacqua, the archdiocese was notified that Brennan had sexually or inappropriately touched more than 20 boys, many from the schools or the parishes where he was assigned,” Williams said.  “A serial predator is behind bars.”

Brennan has never faced criminal charges before because of all the previous accusations fell outside the legal statute of limitations.
In a statement, the Archdiocese of Philadelphia says Brennan was removed from active ministry in September 2005 and has not been permitted to function as a priest anywhere since that time.

The archdiocese also says its petition to the Vatican to officially laicize Brennan — that is, remove him from the priesthood permanently — is pending.

MORE NEWS: Upper Darby Police Investigating Death Of Newborn Found In Bag

Brennan waived his extradition hearing and was brought back to Philadelphia Thursday afternoon.