The California Department of Corrections and Rehabilitation (CDCR) is investigating the killing of an inmate at Soledad Valley State Prison.
Cory J. Benton, 40, was reportedly killed with what officials described as an "inmate-manufactured weapon."
CDCR officials say Benton was stabbed multiple times and died on the way to an outside hospital.
The suspects in the case have been identified as Alberto T. Valades, Jose L. Valle, and Jimmy M. Martinez. All three are currently serving life sentences.
Valle and Martinez were previously convicted of murder. Valades was convicted of second-degree robbery.
The three men have reportedly been moved to restricted housing pending a full investigation.
Benton had been incarcerated at Soledad Valley State Prison since 2012. He was serving a sentence of 25 years for assault with a deadly weapon, assault with force likely to produce great bodily injury, and gang enhancements related to a fight at a party in Santa Maria on Feb. 14, 2010.
