The serial killer known as the "I-5" strangler was found dead in his California prison cell and officials are investigating his death as a homicide.
Roger Kibbe, 81, was found dead shortly after midnight on Feb. 28, according to the California Department of Corrections and Rehabilitation.
A correctional officer was conducting a population count and saw Kibbe lying unresponsive on the floor of his cell. His cellmate, Jason Budrow, was standing over the serial killer, according to officials.
Medical staff tried to provide care for Kibbe and he was taken to the prison health care facility for treatment, according to the department. He was pronounced dead about 40 minutes after being found.
Kibbe was sentenced in 2009 to life in prison without parole on two counts of first-degree murder. He was also serving life sentenced for a first-degree murder count in 1991.
He has been in prison since June 1991.
Kibbe raped and killed at least seven women over two decades and left the bodies along freeways in the Sacramento, California, area.
While serving time for his first murder conviction, DNA helped tie Kibbe to other cold cases, according to media reports. Kibbe then confessed to other killings. He even tried to help investigators find the remains of one of his first victims.
Budrow, 40, was also in prison for life after he was convicted of first-degree murder in 2011, officails noted.
Prison officails continue to investigte Kibbe's death.