Richard Ramirez, a notorious convicted serial killer known as the "Night Stalker" for murdering 13 people and terrorizing Southern California in the mid-1980s, has died.

Ramirez, 53, was on death row at San Quentin State Prison in Marin County, Calif. He was pronounced dead at a Marin hospital early today morning of natural causes, San Quentin Prison Lt. Sam Robinson told ABC News.

He had been housed on death row for decades and was awaiting execution, even though it has been years since anyone has been put to death in California.

Known as the "Night Stalker," Ramirez would enter homes at night through unlocked doors and windows. Victims were shot or stabbed to death, and Satanic symbols were found at some of the murder scenes.

While attempting a carjacking in 1985, Ramirez was captured and beaten by East Los Angeles bystanders until police arrived.

Ramirez's murder trial took four years and began with him famously raising his hand in court to reveal a pentagram on it as he declared, "Hail Satan."

The trial ended in 1989 when Ramirez was convicted of 13 counts of murder, and numerous counts of attempted murder, sexual assault and burglary.

Lennox McLendon/AP Phot