Forensic investigators say new tests on the grounds of Charles Manson's former ranch reveal the likely existence of two more decades-old graves.
The findings confirm popular theories that unknown victims still lay buried out on the edge of Death Valley at Manson's California Barker Ranch, where the convicted murderer and his followers holed up in the 1960s.
"A statement attributed to Susan Atkins is that there are eleven murders that they'll never find out about," Sgt. Paul Dostie of Mammoth Lakes Police said. Atkins, one of Manson's followers, is serving a lifetime sentence in California for murder.
The Associated Press reports that Atkins boasted to her cell mate on Nov. 1, 1969, that there were "three people out in the desert that they done in." In the absence of bodies, however, the claim was long dismissed.
Emmett Harder is a former gold prospector who knew Manson and his followers in those days and says he heard stories that Manson "killed at least five drifters and hippies out there."
"One of the girls, for instance, that didn't get along with Watson and Manson, they took her out, walked away with her, came back without her, and nobody saw her again," Harder said, alluding to Charles "Tex" Watson, who was Manson's right-hand man.
Now, 39 years later, Harder guided an unofficial group back to Manson's parched, eerie desert outpost to search for the bodies last month.
The team included two researchers with cutting-edge forensic technology to detect chemical markers of human decomposition, and an anthropologist armed with a magnetic resonance reader.
Along with Dostie, who was off-duty, and his cadaver sniffing dog, the group marked several possible locations of graves. They all said the sites should be dug up.
In a 1999 interview with Diane Sawyer, Manson said others committed murder, but not him.
"I never told anybody to do anything other than what they wanted to do," he told Sawyer from prison.
"And if they wanted you to do murder, that was OK with you?" Sawyer asked.
"That was none of my business, woman," he said. "I'm a convict. I'm an outlaw. I'm a rebel. I'm not a Sunday school teacher."
Fear ripped throughout Los Angeles and the country after the spate of 1969 so-called "Manson Murders," in which people were seemingly picked at random and slaughtered in their homes.
Victims included actress Sharon Tate — eight months pregnant — and her friends, shot and stabbed in their home on Cielo Drive in Benedict Canyon.
Then the next night, miles from the Tate murders in Los Feliz, a grocery executive named Leno LaBianca and his wife were tied up and stabbed in their home.
Sharon Tate's sister, Debra Tate, is still hoping that Manson doesn't get away with anything and went with the team to the desert.
"It is important for me to be able to give closure to some families," Tate said.
Because Manson is already in prison for life, and rural law enforcement cannot afford to spend money digging into the past, it is likely that nothing will be done.
The Associated Press contributed reporting to this article.