SAN QUENTIN (CBS SF) — Condemned inmate Phillip Jablonski, on San Quentin’s Death Row for killing his wife and mother-in-law in their Burlingame home in 1991, has been found dead inside his prison cell, officials announced Monday.

Corrections officials said guards discovered the 72-year-old Jablonski unresponsive in his cell Friday at 1:10 p.m. and he was pronounced dead 20 minutes later. The Marin County Coroner will determine the cause of death.

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A San Mateo County jury sentenced Jablonski to death on Aug. 12, 1994 for the first-degree murders of his mother-in-law, Eva Petersen, 72, and his wife, Carol Spadoni, 46.

Evidence presented at the trial revealed that Spadoni was shot, suffocated with duct tape, then stabbed, while Petersen was sexually assaulted and shot inside their Burlingame home on April 23, 1991.

Officials said Spadoni had married Jablonski in 1982 after he had been released from prison, serving 12 years for the murdering his former wife, Linda Kimball, in July 1978.

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When Jablonski was released from prison in 1990, he told his parole officer that he wished to live with Spadoni, but she said she did not want him living with her because she was afraid of him, according to court records.

Jablonski was forbidden by his parole conditions from going to Burlingame, where Spadoni lived at a home with her mother, but he went there and killed them both.

Jablonski was also convicted of the 1991 murders of 38-year-old Fathyma Vann in Indio, Calif., and 58-year-old Margie Rogers in Grand County, Utah.

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Since 1978, when California reinstated capital punishment, 82 condemned inmates have died from natural causes, 27 have committed suicide, 13 have been executed in California, one was executed in Missouri, one was executed in Virginia, 14 have died from other causes and five – including Jablonski – are pending a cause of death. There are currently 728 offenders on California’s death row.