A Utah teenager admitted Tuesday that he attacked and raped a woman who was jogging on a Sandy trail earlier this year.

Rainie’r Craig Peterson, 16, pleaded guilty to charges in both juvenile and adult court, admitting he grabbed and assaulted a 50-year-old woman as she ran alongside the TRAX line near Sandy on March 19.

As part of a plea deal, he admitted to a charge of aggravated kidnapping in juvenile court Tuesday morning. Later, he went before another judge and pleaded guilty as an adult to first-degree felony aggravated sexual assault.

“I hit her and dragged her into a ditch and forced sex upon her,” Peterson told a juvenile court judge, according to FOX 13.

This blended plea will allow the boy, who was 15 at the time of the attack, to remain in a juvenile facility — where he would receive more services and treatment — before going to the adult prison at age 21.

Peterson will return to a juvenile courtroom Sept. 11 where a judge will likely impose a stay at a secure juvenile detention center for the aggravated kidnapping. The teen also faces a sentence of up to life in the adult prison for the sexual assault, but that sentence won’t be handed down until after he serves his time in the juvenile system.

The victim testified in June that on that March day, she was flagged down by a young man on a scooter who asked to use her phone.

“It seemed like he needed help,” the woman said. “So I stopped.”

She quickly realized, however, that the stranger was only pretending to make a call — and demanded her phone back, then reached toward him. He then grabbed her and pulled her down in a ravine, where a scuffle ensued.

He punched her, she testified, and began strangling her. He told her she was going to die that day, before proceeding to sexually assault her three separate times.

The woman testified that she tried to run away from her attacker several times, and on one attempt, he hit her over the head with a bottle, shoved glass near her eye and threatened to slit her throat. She was finally able to escape on her third attempt. The beaten woman found a passerby, who called 911.

The Salt Lake Tribune generally does not identify alleged victims of sexual assault and does not identify youth defendants unless the case has been moved to the adult court system.

After the attack, police found surveillance video from two TRAX stations and a train showing a male who matched the description the woman gave police of her attacker. The images were forwarded to law enforcement at two area high schools, according to court papers, and a resource officer from Jordan High School recognized the teen, who he said regularly rides a scooter. School surveillance video showed the teen wearing clothing that matched the description the woman gave police, according to court documents.