ADAMS COUNTY, Colo. — A former assistant pastor was sentenced to 13 years in prison Tuesday for sexually assaulting a girl that initially was covered up by church leaders and the girl’s father, the 17th Judicial District Attorney’s Office said.

Robert Wyatt, 51, repeatedly sexually assaulted the now-15-year-old girl whose family attended Agape Bible Church in Thornton, prosecutors said.

Wyatt gained trust from the girl and her parents, and got access by home-schooling her in his residence.

The girl told investigators the inappropriate touching started when she was 12 and had been going on for nearly two years.

In March 2016, Wyatt offered to take the girl on a field trip but instead they went to a hotel where he sexually assaulted her, prosecutors said.

“Mr. Wyatt describes this as a ‘stupid decision’ but this wasn’t a mistake. He saw he could manipulate the victim and her family. It was a calculated, methodical decision by the defendant to take advantage of this young girl,” senior deputy district attorney Patrick Freeman said.

“He is a sexual predator.”

Church leaders and the girl’s father tried to keep Wyatt’s crimes from being reported to police.

“Those who attempted to hide him from justice share blame,” Freeman said.

“You were in a position of trust with the church and as her teacher,” Adams County District Judge Don Quick told Wyatt at the sentencing hearing.

“You preyed on her emotional and physical vulnerabilities. Over and over again you planned how to groom her so that you could commit these acts. You took advantage not just of her body but her heart, telling her that you loved her.”

Quick was also critical of church leaders and the girl’s father for how they shifted blame to her and trying to handle things internally.

“I’m still shocked at how certain adults responded to this,” Quick said. “She didn’t put him in prison. He put himself in prison.”

Wyatt pleaded guilty in July to attempted first-degree assault and sexual assault on a child.

He was charged last year with one count of sexual assault on a child, one count of sexual assault on a child as a pattern of conduct and one count of sexual assault on a child by a person in a position of trust.