Convicted serial killer Lonnie Franklin Jr., known as 'Grim Sleeper,' dies on death row at 67

SAN QUENTIN, Calif. (KABC) -- Convicted serial killer Lonnie Franklin Jr., known as the "Grim Sleeper," has died on death row at the age of 67, according to authorities.

Franklin was found unresponsive in his single cell at San Quentin State Prison on Saturday evening, according to a press release from the California Department of Corrections and Rehabilitation. His cause of death, pending an autopsy, has not been determined, though authorities said there were no signs of trauma.

In 2016, Franklin was sentenced to death in the slayings of 10 women, including a 15-year-old girl, over two decades in South Los Angeles during the crack epidemic.

The killings took place between 1985 and 2007, and were dubbed the work of the Grim Sleeper because of an apparent 14-year gap after one woman survived a gunshot to the chest in 1988.

Franklin was linked at trial to 14 slayings, including four women he wasn't charged with killing. Police have said he may have had as many as 25 victims.

'Grim Sleeper,' convicted serial killer Lonnie Franklin Jr., sentenced to death

During his sentencing, authorities stated some of the former mechanic and sanitation worker's victims were prostitutes and most had traces of cocaine in their systems.

All the victims were either shot or strangled, and their bodies found dumped in alleyways, bushes, and dumpsters or hidden under mattresses.

Franklin was still awaiting his execution date at the time of his death.

He was granted a reprieve a year ago when California Gov. Gavin Newsom halted the execution of more than 700 condemned inmates on the nation's largest death row for at least as long as he's governor.

California hasn't executed anyone since 2006, under then-Republican Gov. Arnold Schwarzenegger, and inmates are far more likely to die of old age.

The Associated Press contributed to this report.