TROY, Ohio (AP) — The one-story, brick ranch-style home blends into the working-class neighborhood along Nutmeg Square in this western Ohio city, offering no signs of the terrible secrets it once concealed.

Its former owner will return to court Tuesday in Dayton to be sentenced for guilty pleas to child rape and related charges in a haunting case that experts call unusual because the perpetrator was an adoptive father and the victims were three boys in his care. The pleas have all but ensured he will spend the rest of his life in prison.

The 40-year-old man, whom The Associated Press isn't naming to protect the children's identities, said in an interview that he had been a foster parent, youth basketball coach and substitute teacher for years without any problems. He said he didn't adopt the boys with bad intentions.

"I always wanted to protect kids," he said during one of two interviews at the Miami County Jail. "Somewhere along the line, things went wrong."

In an era of stunning cases of sexual abuse of young boys by respected authority figures — priests, Boy Scout leaders, an assistant coach at a famed football program — the repeated rapes of boys by an adoptive father who also arranged for two other men to rape one adopted son shocked his unsuspecting neighbors, investigators and children's services officials.