WEST JORDAN — A Midvale teenager admitted Tuesday that he attacked a 50-year-old jogger on a Sandy trail who had stopped to help him and then sexually assaulted her.

Rainier Craig Peterson, 16, told a judge that he first asked to borrow the woman's phone on March 19 before he beat her.

"I hit her and dragged her into a ditch and forced sex upon her," he said Tuesday.

Peterson pleaded guilty in 3rd District Court to aggravated sexual assault, a first-degree felony, as part of a plea deal that is expected to earn him an eventual prison sentence.

He had agreed to face that charge as an adult just moments earlier in a juvenile courtroom down the hall.

The teen sat next to his attorneys during the juvenile proceeding as his mother listened over the phone. At one point, he gripped the table, and his defense attorney William Russell put a hand on his client's back.

Peterson replied "yes," when 3rd District Judge Heather Brereton asked him if his attorney was correct in saying that he forced the woman to submit to rape under the threat of death.

In June, the jogger testified that she stopped to help him in Dimple Dell Regional Park after he asked to use her phone. But the teen, who was 15 year old at the time, beat her when she tried to get it back, sexually assaulted her and tried to shove a glass shard into her eye, telling her, "You will die today," she recalled. DNA results from the woman's rape kit matched the teen, a detective testified at the June hearing.

On Tuesday, Peterson also pleaded guilty to aggravated kidnapping, a first-degree felony, but that case will remain in the juvenile system. Sentencing is scheduled for Sept. 11.

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Teen agrees to plea deal in violent assault of jogger, attorney says

A teen accused of sexually assaulting and attempting to strangle a 50-year-old jogger after dragging her into a ravine is expected to admit to some charges later this month.

Prosecutors requested a judge wait to sentence Peterson for the sex assault conviction until his release from a juvenile detention center, where he is expected to serve his sentence in the kidnapping case. The maximum time defendants can spend in the juvenile system is until they turn 21.

Spending the next five years in the juvenile system's care will allow the teen to receive treatment while still remaining in a secure facility, said Coral Sanchez-Rose, deputy Salt Lake County district attorney.

Peterson's time there will likely end on his 21st birthday, but it could end sooner if youth parole officers release him earlier or if he is convicted of another crime. Under sentencing guidelines, Peterson's sexual assault conviction in adult court carries a possible sentence of at least 15 years and up to life in prison, but prosecutors agreed to recommend that the minimum be lowered to 10 years.

In exchange for the guilty pleas, remaining charges were dropped, including attempted aggravated murder, two counts of aggravated sexual assault and aggravated robbery, all first-degree felonies.

Those who have experienced sexual abuse or assault can get assistance from Utah's statewide 24-hour Rape and Sexual Assault Crisis Line at 888-421-1100.

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