Butler police Tuesday arrested a city man on charges he sexually assaulted a young girl over a six-year period.

Zachariah Thomas Morrow, 24, allegedly started molesting the girl in 2008 when she was 6 years old. The sexual abuse continued into this year, said Butler Police Capt. David Dalcamo.

Morrow confessed to the charges during an interview with Dalcamo last week, according to court documents.

District Judge Pete Shaffer on Tuesday arraigned the defendant on 133 charges, mostly felonies for sexually assaulting a child. He is being held in the Butler County Prison on $75,000 bail.

Police said they began investigating last week after the girl, who lives in Allegheny County, told a family member that Morrow had sexually assaulted her for years. The alleged abuse happened in Butler and the surrounding area, Dalcamo said.

The girl's father notified police, who were assisted in the investigation by the Butler County Children and Youth Services agency and the Butler County Alliance for Children.

The girl, 12, was interviewed Friday. Later that day, Dalcamo interviewed Morrow.

The suspect waived his right to speak to an attorney and almost immediately offered up his videotaped confession, Dalcamo said, corroborating all of the girl's allegations.

Among the charges against Morrow are 13 counts each of involuntary deviate sexual intercourse by forcible compulsion, involuntary deviate sexual intercourse with a child and aggravated indecent assault of a child, all first-degree felonies.

His preliminary hearing is set for Monday.