BAKERSFIELD, Calif. (KGET) -- An inmate at Kern Valley State Prison died Thursday after an apparent attack with an inmate-manufactured weapon, his cellmate also suffering injuries, prison officials said. Jacob Kober, 35, was pronounced dead at 7:52 p.m., about 30 minutes after prison staff found him wounded and unresponsive in his cell, according to a release from the California Department of Corrections and Rehabilitation. His cellmate, Matthew Perez, 39, also had injuries and was taken to an outside medical facility, the release says. An inmate-manufactured weapon was found in the cell, according to CDCR. Both men's wounds appeared to have come from it. An investigation is ongoing. Kober was serving a life term after being convicted of first-degree murder in Alameda County. Perez is serving 18 years for a 2012 conviction of assault with a gun in Monterey County, eight years for a 2014 prison assault and two years for a 2016 conviction for having drugs in prison.