SEAL BEACH, CA — An inmate who was sentenced to death for the murder and rape of a 70-year-old Seal Beach woman in the ’80s died in prison, state officials announced.

Benjamin Watta, who was placed on condemned status for the first-degree murder of 70-year-old Simone Sharpe, died on Dec. 22 while incarcerated at Pelican Bay State Prison in Crescent City. He was 80 years old.

According to the California Department of Corrections and Rehabilitation, Watta was found unresponsive in his assigned cell at around 11 a.m.

Responding staff tried to save his life, but he was pronounced dead by paramedics at 11:37 a.m. His cause of death was not officially determined.

Watta was originally served his condemned sentenced in 2009 for the murder of 70-year-old Simone Sharpe.

According to the Orange County District Attorney, Sharpe had been helping her vacationing neighbors for several days when she went missing on Dec. 23, 1980.

On Dec. 24, Sharpe’s son noticed that his mother was missing and went to the neighbor’s house to look for her.

When he entered the neighbor’s home, he found his mother murdered in a bedroom, wedged between the bed and the wall. According to county prosecutors, Sharpe had been raped, strangled and suffocated.

The case remained unsolved for over 20 years until March 21, 2001, when new DNA technology linked Watta to the murder. At the time, Watta was in custody in Florida for shooting and attempting to murder his then-girlfriend.