FRESNO, Calif. -- National Park Service officials said the Death Valley ranch where Charles Manson was arrested will be closed for a second time this year to search for possible human remains.

A press release Thursday said that Barker Ranch will be closed for up to four days later this month.

A team of forensic researchers from Tennessee's Oak Ridge National Laboratory found possible unmarked graves at the site in February that they believe could be the bodies of additional Manson victims.

The park was briefly closed in April, but digging was put off because a piece of high-tech soil testing equipment was damaged en route to the site. Authorities said they wanted to conduct tests using lasers before disturbing the soil.

Manson and his followers hid out in the park after their 1969 killing spree.