SAN QUENTIN (CBS SF) — Lonnie D. Franklin Jr., the infamous ‘Grim Sleeper’ killer who was on San Quentin’s death row for the murders of nine women and one teenage girl in South Central Los Angeles, has been found dead in his cell.

Prison officials said the 67-year-old Franklin was found unresponsive in his cell around 7:20 pm. Saturday. He was pronounced dead a short time later. There was no evidence of trauma.

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The Grim Sleeper Killer, Lonnie Franklin Jr

Lonnie Franklin Jr., a convicted serial killer known as the “Grim Sleeper,” was sentenced in Los Angeles Superior Court, Aug. 10, 2016. (Al Seib via AP)

The Marin County Coroner will determine the cause of Franklin’s death. Prison officials said there have been no reported cases of coronavirus at San Quentin.

Franklin was sentenced to death in Los Angeles County on Aug. 10, 2016, for 10 counts of first-degree murder and one count of attempted murder committed between 1985 and 2007. He arrived onto death row on Aug. 17, 2016.

Detectives investigating a series of murders in South-Central Los Angeles stumbled upon Franklin as a suspect in the slaying when they got a DNA hit on his son, Christopher, who had been convicted of a felony weapons charge.

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When Christopher was eliminated as a suspect, detectives began looking into other members of his family.

An undercover police officer placed Franklin under surveillance and tracked him to a favored pizza parlour. Posing as a waiter, the undercover officer retrieved dishes, silverware, glasses and pizza crusts to obtain Franklin’s DNA. Saliva found on the victims established a DNA match linking Franklin to the deaths.

Franklin used the same .25 caliber gun in the attacks and kept photos of his victims as trophies in his home.

He was arrested and convicted of the 10 murders and one attempted murder after a trial that stretched for several months. A jury found Franklin guity after one day of deliberations. He was sentenced to death on August 10th, 2016. It was exactly 31 years after the death of his first confirmed victim, Debra Jackson, in 1985.

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Since 1978, when California reinstated capital punishment, 82 condemned inmates have died from natural causes, 27 have committed suicide, 13 were executed in California, one was executed in Missouri, one was executed in Virginia, 14 have died from other causes and eight – including Franklin – are pending a cause of death. There are 727 people on California’s death row.