State corrections officials have launched a homicide investigation after a convicted killer from Alameda County died following an incident at a Central Valley prison Thursday evening.

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.

A Livermore man who was convicted of a 2012 murder died in prison Thursday after an apparent attack with an inmate-manufactured weapon, prison officials said. Jacob Kober, 35, was an inmate at Kern Valley State Prison.