(CNN) -- Authorities will continue to test soil at a California ranch that was once home to cult leader Charles Manson, looking for more evidence of buried bodies before any excavations begin, the county sheriff announced Friday.
Earlier this month, search crews found indications that human remains might lie within a few yards of Barker Ranch, the onetime hideout of the "Manson family."
The sites were first identified by trained dogs. Testing equipment from the Oak Ridge National Laboratory also indicated the presence of remains, Sgt. Paul Dostie of the Mammoth Lakes, California, Police Department told CNN.
But Inyo County Sheriff Bill Lutze said Friday that after analyzing information from the sites, he decided further testing was necessary.
"Myers Ranch is private property, Barker Ranch is national park property," Lutze said in a written statement. "Both are compelling reasons to be as cautious as possible and use every reasonable testing method available before disturbing the ground with excavation."
Myers Ranch, adjoining Barker Ranch, was owned by a relative of a Manson family member and also served as a hideout.
Methods of testing the soil "with minimal intrusion" are available, the sheriff's office said, and will be able to determine "with a high degree of reliability" whether bodies are buried there.
"Forensic teams will focus on a very few spots in which search dogs recently indicated possible findings of dead bodies with some consistency," the sheriff's statement said. "The various dogs gave inconsistent findings at many spots on the ranch property and all dogs were not controlled in the same manner accepted by recognized dog search organizations."
The testing will be closed to the news media, Lutze said, to protect the integrity of the process and the property rights of the owner. Testing results will be released, however, probably in late April, the statement said.
After Sgt. Dostie's dog and another dog, from NecroSearch, a nonprofit organization that specializes in finding clandestine graves, indicated the possible presence of human remains, testing equipment from Tennessee's Oak Ridge laboratory indicated two likely grave sites and a third possible grave site, Dostie told CNN.
Manson and four other "family" members were convicted of murder and other charges in connection with a two-night spree in August 1969 that included the slaying of actress Sharon Tate. The slayings -- and Manson and his family members -- transfixed the nation. E-mail to a friend