Police say a missing 18-year-old South Jordan woman overdosed on drugs before her body was dumped by a panicked friend in the foothills above Bountiful.

The body of Amelia Sorich was discovered about 7:40 p.m. Monday by hikers about three miles north of the Bountiful "B" in Bountiful Canyon. Her body was in a ravine about 100 feet off the main dirt road. She had been missing since Saturday.

The Utah state medical examiner positively identified the body Tuesday. The cause of death was determined to be a fatal drug-overdose mixture of cocaine and heroin.

South Jordan Police Sgt. Dan Starks said detectives determined through interviews that Sorich voluntarily took the potent cocaine-heroin mixture, also known as an "eight ball."

Late Tuesday afternoon, police booked two adults, a 19-year-old male and an 18-year-old female, into the Salt Lake County Jail for investigation of desecration of a dead body and evidence tampering.

Michael Bellows, Sorich's LDS bishop, said family and friends of the woman are devastated. He said everyone in her LDS ward who knew her is in disbelief about the way she died.

"No one really believes she was involved in drugs," he said.

Sorich graduated from Bingham High School earlier this month, Bellows said, and was working two jobs while preparing to attend college this fall. He said she was a good student, excelling in math, and when he saw her on graduation day, he said, "there was no indication whatsoever" that she was a drug user. Bellows has known Amelia nearly six years.

Just as news of the body's discovery was becoming public Tuesday morning, a 19-year-old Holladay man walked into South Jordan police headquarters and told investigators he knew what happened to the missing woman and where to find her.

The male had been interviewed the night before until 2 a.m. Between 9 and 10 a.m. Tuesday, he went back voluntarily to offer what he knew, Starks said.

"His conscience apparently got the better of him," Starks said.

After the man was interviewed again Tuesday afternoon, he was arrested.

Investigators believe Sorich and the two others were partying at a home near 450 E. and 14000 South on Saturday evening about 11 p.m.

Sometime between 3 a.m. and 4 a.m. Sunday, Sorich stopped breathing, became unconscious and began spitting up blood, Starks said. At some point her friends realized she was in trouble, apparently "freaked out" and panicked when they were unable to revive her, he said.