Officials at Salinas Valley State Prison are investigating the death of inmate Robert Tunstall, 64, as a possible homicide that happened on Oct. 5. According to SVSP officials, Tunstall was attacked by another inmate around 8:50 a.m. Staff said after they gave orders to stop the attack and began to perform life-saving measures, Tunstall was pronounced dead at 9:21 a.m. SVSP investigators say they have recovered an inmate-made weapon and notified the Monterey County Coroner's office as they will determine Tunstall's official cause of death. Tunstall was admitted to Solano County on Dec. 23, 1976, to serve life with the possibility of parole for first-degree murder. According to SVSP investigators, they have identified Lawrence Adams, 42, as the suspect who may have murdered Tunstall.Adams was already serving life after charges arson to property and a conviction for possession of an explosive device.According to SVSP, Adams was sentenced in Monterey County to serve 12 years for assault with a deadly weapon and possession/manufacture of deadly weapon by a prisoner, both are in-prison offenses.