Mass murderer Charles Manson is to be quizzed after two more burial sites were found near the desert ranch home of his sinister cult.
Evil Manson and his "Family" killed seven people - including pregnant film star Sharon Tate - in an orgy of violence in 1969.
But following the discovery of the graves earlier this month near the cult's abandoned Barker Ranch in Death Valley, California, police have reopened scores of missing people files.
Detectives will this week question the 73-year-old at the state's Corcoran State Prison, where he has been incarcerated for 37 years.
Forensic experts have already established that soil samples from the new graves contain traces of human DNA.
Crime scene investigators are now preparing for a painstaking dig using ground-penetrating radar.
Retired homicide detective Sgt Bill Gleason, who worked on the original case, is helping the investigation.
He said: "There have been rumours of other murders for decades but until now we haven't had anything concrete to work on. This is a major breakthrough."
Mad Manson and his hippie clan believed the end of the world - which they referred to as Helter Skelter - was close and thought they could accelerate it by provoking a race war through killing affluent white people.
Sharon Tate, who was eight months pregnant, was found dead at the Beverly Hills home she shared with her husband, film director Roman Polanski.
The word "Pig" was scrawled in her blood on the front door and inside walls.
Manson had told his drug-crazed devotees that Barker Ranch was a secret city called The Bottomless Pit, where they could ride out the apocalypse and emerge as America's new leaders.
He has remained in isolation at Corcoran Prison, where only armed officers in pairs have contact with him.
In one five-year period between failed parole applications in 1997 and 2002, Manson was charged with 17 "serious" jail offences, including possession of a makeshift weapon, arson and threats to kill guards.
At the time, one guard said: "He somehow managed to set his mattress on fire. He stood there behind a wall of flames in his cell cackling uncontrollably as the riot squad put the fire out."
