Inmate Supplementally Booked for Murder Following Death at West Valley Detention Center
RANCHO CUCAMONGA, CA — On Monday, January 19, 2026, at approximately 11:12 p.m., deputies at the West Valley Detention Center in Rancho Cucamonga located an inmate, identified as 38-year-old Zacarias Joseph Ruiz, unconscious in his cell. According to the San Bernardino County Sheriff’s Department, Ruiz exhibited physical trauma at the time of discovery. Deputies and facility medical staff administered lifesaving measures until emergency medical personnel arrived. Ruiz was transported to a nearby hospital, where he was pronounced deceased the following day.
The Sheriff’s Specialized Investigation Division – Homicide Detail assumed the investigation into the in-custody death. Detectives determined that Ruiz and his cellmate, 26-year-old Isaiah Mark Bailon, had been involved in a physical altercation prior to the discovery of Ruiz. Consequently, Bailon was supplementally booked for murder. Bailon had been in custody since December 31, 2025, following an arrest for attempted murder and robbery.
Records indicate that Ruiz had been in custody since May 5, 2025, on charges of criminal threats and domestic violence. An autopsy is scheduled to determine the official manner and cause of death. The Homicide Detail maintains an ongoing investigation and has requested that anyone with information contact Detective E. Badillo.
