LAS VEGAS (KLAS) — An investigation is under way after an inmate died while in custody at the Mohave County (Arizona) Adult Detention Facility in Kingman.

Raul Martinez, 26, of Bullhead City was in the medical ward of the Mojave County Jail for observation. He was refusing to eat, according to information released by the Mohave County Sheriff’s Office.

Just before 2:30 a.m. on Thursday, medical personnel were summoned when Martinez was unresponsive.

“Martinez was the sole occupant of the cell and had been checked approximately fifteen minutes prior to being found unresponsive,” according to the sheriff’s office.

Life-saving efforts including CPR, Narcan and a defibrillator failed, and Martinez was transported to Kingman Regional Medical Center via ambulance where he was pronounced deceased.

There were no signs of trauma or foul play, according to the sheriff’s office.

Detectives with the Mohave County Sheriff’s Office are investigating. An autopsy will be conducted to determine the cause of death.

Martinez was booked on July 23 on a charge of “unlawful flight” and a warrant, according to the sheriff’s office.

Kingman is about an hour and a half southeast of Las Vegas on U.S. 93.