LAS VEGAS (KLAS) — A Nevada coroner’s office has determined the cause of death for Naomi Irion to be gunshot wounds to the head and chest. Irion’s body was found in a remote gravesite in Churchill County, near Reno and the state’s western border with California.

On April 1, detectives with the Lyon County Sheriff’s Office charged and booked Troy Driver for open murder with the use of a deadly weapon, robbery, burglary, and destruction of evidence. The Churchill County Sheriff’s office and the Lyon County Sheriff’s Office also announced Thursday, March 31 that they are investigating the 18-year-old’s death as a homicide.

Troy Driver (Image: Lyon Co. Sheriff’s Office)

The Washoe County Medical Examiner’s Office confirmed Irion’s identity on Wednesday, March 30. She was last seen alive on March 12 getting into the passenger seat of her car outside of a Walmart around 5 a.m.

Officials said video surveillance showed a person from a nearby homeless camp lurking near vehicles around the same time of Irion’s disappearance. The man was then seen getting into Naomi’s car and leaving.

Deputies initially arrested Driver on a charge of first-degree kidnapping. Court documents show Driver is accused of kidnapping her “for the purpose of committing sexual assault and/or purpose of killing her.”

Driver was set to appear in court Tuesday, April 5, for a pretrial status hearing, but a judge continued that hearing until May 10, according to the Associated Press.