A “large-scale” riot broke out at California Men’s Colony prison near San Luis Obispo on Sunday, leaving one inmate dead.
The riot broke out about 10:50 a.m. in the yard of the medium-security East Facility, according to the California Department of Corrections and Rehabilitation. More than 160 inmates were involved in the riot, and its cause is currently unknown, the CDCR said. CMC houses 4,169 inmates, according to the CDCR.
Multiple inmates received stab wounds, the CDCR said, and nine inmates were taken to outside hospitals for further treatment.
One of the inmates, identified as 25-year-old Matthew Cook, was pronounced dead at 1:05 p.m., the CDCR said. According to the department, Cook had been incarcerated since April 2015 and was serving a 13-year, 8-month sentence for “several counts” of first-degree burglary.
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No prison staff was injured during the riot and no deadly force was used, the CDCR said.
According to Sierra Vista Regional Medical Center spokesman Ron Yukelson, the hospital was notified of a “mass casualty incident” about noon and was told by CMC to expect three trauma patients and six patients with less-serious injuries. The hospital called off the “mass casualty incident” at 1:20 p.m., Yukelson said.
The hospital uses the term “mass casualty incident” when it has been told to expect three or more trauma patients and need more staff, Yukelson said. As of 1:45 p.m., the hospital had received two trauma patients and four patients with less-serious injuries.
The prison ended its visiting hours on Sunday, and all visitors were escorted out of the prison after the riot broke out, said Lt. Monica Ayon, a spokeswoman for CMC.
“Visiting occurs on Saturday and Sunday, so we will reassess as we approach next weekend,” she wrote in an email.
According to the CDCR, authorities have limited how much inmates can move around the prison as officials investigate the incident.