Search for remains at former Manson ranch called off

Investigators have called off a dig at the former California ranch of Charles Manson after a two-day search for undiscovered graves came up empty.

A crew of 20, using technology not available 40 years ago, ended their excavation of the site Wednesday, a day earlier than planned after work went faster than scheduled.

"There have been no human remains found," Inyo County Sheriff Bill Lutze said Wednesday. "We're finishing up this site and that'll be it for the day — nothing."

Lutze said investigators were glad they didn't find evidence of any additional victims.

"If we came up with nothing, that's great because [it means] there's nobody out here buried," he said.

The search came after a group that included a police investigator with a cadaver-sniffing dog and an anthropologist with a magnetic resonance reader found two sites that could be graves last February.

All the two-day search recovered was a recent .38-calibre shell casing and animal bones.

Searchers scoured an area of the Panamint Mountain range using radar, magnetometers and portable gas-chromatograph and mass spectrometers that can detect chemical markers characteristic of bodies in decomposition.

But researchers said the rugged terrain and the rock-filled dry soil made it difficult to use some of the equipment and determine what was underground.

As well, plants that exude unusual chemicals and rocks with magnetic properties were throwing off their equipment, they said.

"I haven't been this frustrated in a very long time," Arpad Vass, a senior researcher at the Oak Ridge National Laboratory, told the Associated Press.

Vass said the excavation was a learning process.

"We're trying to improve the science. It's in its infancy," he said. "There could be additional people out there. But unless there are leaps in this kind of science, we'll never know."

Manson and his followers hid at the ranch following the 1969 murders of actress Sharon Tate and six others in Los Angeles.

For years there have been rumours that hitchhikers and runaways who ended up at the camp may have also been victims.