FREMONT, Ohio (AP) — Investigators say a high school student’s essay about overcoming obstacles has led to an Ohio man pleading guilty to raping three sisters years ago.

Detectives in northwest Ohio’s Sandusky County say they began investigating after school officials alerted a children’s services agency and the sheriff’s office.

Sheriff Sgt. Kenneth Arp says one of the sisters wrote in the essay that she’d been sexually abused as a child.

He says the victims were at first reluctant to come forward, but all three told of being raped. He says the youngest girl was 7 when she was first sexually abused.

A judge on Tuesday sentenced 43-year-old Anthony Knight to 20 years in prison after he pleaded guilty to felony rape charges.

A message seeking comment was left with Knight’s attorney.