A former school security guard accused of keeping a teenage runaway in his home for a decade and having sex with her pleaded guilty Tuesday, the opening day of his trial.

Thomas John Hose, 49, took in the 14-year-old girl and kept her from leaving the tiny home he shared with his parents and son, prosecutors said. Tanya Nicole Kach, now 25, has said the two regularly had sex during her captivity.

He was sentenced to five to 15 years in prison.

Hose, of McKeesport, had been a security guard at Kach's school, and Kach went to live with him in February 1996. She has said she had a crush on him.

She eventually revealed her identity as a runaway to a deli owner she had befriended, leading to Hose's arrest in March 2006.

The Associated Press normally does not name victims of suspected sex crimes, but Kach has spoken with reporters about her experience.

During the hearing, Kach read a letter to Hose, her voice faltering and her eyes welling with tears.

"I just want to know why you did what you did to me. Why?" Kach asked. She said Hose took away her innocence and made her feel as though no one loved her.

"It's so sad to say, but I was nothing but a puppet," she said, saying Hose controlled what she wore and ate and even how she styled her hair. "I'm not that dominated puppet anymore."

She said he repeatedly told her: "Oh, you're just a pretty face. You're so stupid, you'd be nothing without me."

Hose apologized: "Only God knows how sorry I truly am."

But he also said Kach repeatedly told him: "Thank you, without you, I'd be dead or in the streets."

Hose's comments drew a rebuke from Allegheny County Judge John Zottola: "I think, Mr. Hose, you give yourself too much credit."

Kach is in therapy but has finished her first semester of college and is volunteering at a senior home, said Lawrence Fisher, her attorney in a civil case against Hose.

Hose's trial had been scheduled to begin Tuesday, but instead he pleaded guilty to statutory sexual assault, three counts of involuntary deviate sexual intercourse, two counts of indecent assault and one count each of endangering the welfare of children, corruption of a minor, interference with custody of children and aggravated indecent assault. He was not charged with kidnapping.