Today, Inyo County sheriff's investigators and scientists packing portable ground-penetrating radar, magnetometers and shovels will convoy to the Barker Ranch on a mission to confirm or put to rest such speculation.
The search at the property, which is at the southern end of Death Valley National Park in terrain so rough it can only be reached by four-wheel-drive vehicles, was expected to continue through Thursday in temperatures expected to exceed 100 degrees.
Wild-eyed career criminal Manson directed the gruesome forays that resulted in the massacre of Sharon Tate, three friends and a teenager at the pregnant actress' Benedict Canyon home, and the slaying of a couple in Los Feliz the next night.
A member of the so-called Manson family later suggested that bodies were buried at the Barker Ranch.
In February, cadaver-sniffing dogs led by a black Labrador named Buster displayed telltale agitation at two sites on the decrepit ranch, tucked in an arid canyon in the Panamint Range. Buster is owned by Mammoth Lakes Police Department Det. Paul Dostie, a small-town investigator with a penchant for recruiting anthropologists, geneticists and geophysicists for his cases.
"The dogs were trained to alert on the unique combination of odors that make up the smell of dead people," Dostie said in an interview. "They alerted on the same spots at Barker Ranch."
Intrigued by the dogs' enthusiasm, Dostie had soil samples analyzed by scientists who volunteered their services.
The analyses were inconsistent, as were subsequent searches. Facing mixed results, Inyo County Sheriff Bill Lutze authorized four days of exploratory excavation.
In a rare move, the National Park Service closed the ranch to the public pending completion of the investigation.
But on the eve of what has come to be known in these parts as the "Big Dig," some locals were criticizing the effort as a waste of time and money in a sparsely populated county that can ill afford it.
Rock Novak, proprietor of a country store in the isolated ghost town of Ballarat, said, "I've heard so many stories over the years about Barker Ranch. Some say there's 30 bodies out there; some say 24. Some say none at all. We won't know until they dig it up."
Anticipating a crush of journalists and curiosity seekers at his forlorn store offering rock and mineral specimens, antique bottles and cold soda and beer, Novak said he was stocking up on T-shirts emblazoned with Manson's image.
"It's my reputation on the line if we don't find anything," said Dostie, the investigator. "We all hope this isn't another Al Capone's secret vault kind of deal."
He was referring to a TV special hosted by Geraldo Rivera in 1986. The program was broadcast live and featured the opening of a vault believed to have been used by the infamous Chicago mobster. When the vault was finally opened, however, the only things inside were some empty bottles.
The ongoing Barker Ranch investigation has involved forensics experts from the Utah attorney general's office, the private laboratory Evident Inc. of Virginia, an archaeologist from Cal State Long Beach and members of the Anthropology Research Facility at the University of Tennessee in Knoxville, otherwise known as the "Body Farm."
They aim to sweep the property today with radar, magnetometers, lasers and special blue lights that cause bones to glow at a great distance. They also will test soil samples with portable gas-chromatograph and mass spectrometers.
"This is the stuff of television's 'CSI' series," Lutze said in a prepared statement. "Some of this equipment is so cutting edge that it does not exist in the marketplace. This case will dramatically alter how police agencies search outdoor crime scenes in the future."
Locals predicted that investigators might unearth ancient Indian graves. Some park rangers speculated that if human remains are discovered at the ranch, they may be connected to a separate Death Valley mystery: the 1996 disappearance of four German tourists -- architect Egbert Rimkus, 34, his girlfriend, Cornelia Meyer, 28, his 10-year-old son Georg Weber, and Meyer's son Max, 4.
In the late 1960s, the Manson gang roamed the barren Death Valley landscape in dune buggies and prepared for "Helter Skelter," a race war Manson was trying to spark. The phrase was taken from a Beatles song, which Manson believed was encoded with predictions that the conflict would destroy modern civilization. Manson and his followers planned to survive by living in a tunnel, then emerge as leaders of some new world order.
Manson was arrested by law enforcement authorities who discovered him hiding beneath a sink in the rock-and-plaster ranch house five miles up Goler Wash, a narrow rocky canyon that is home to chuckwalla lizards and wild burros and must be traversed via a teeth-rattling serpentine dirt road.
After months of frustration investigating the 1969 murders, detectives got their break when Manson follower Susan Denise Atkins, who was being held at the Sybil Brand Institute in East Los Angeles on separate murder charges, talked to a another prisoner who conveyed incriminating information to authorities.
In 1970 and 1971, Manson, Atkins, Leslie Van Houten, Patricia Krenwinkel and Tex Watson were tried for murder. All were found guilty and sentenced to death. The sentences were commuted to life imprisonment when the state Supreme Court abolished the death penalty.
Their petitions for parole have been repeatedly denied.
Louis Sahagun can be reached at louis.sahagun@latimes.com.