It's not too often that a national park plays a role in a murder investigation, particularly not one out of the "cold file" bin. But authorities think Death Valley National Park just might be holding the four-decade-old remains of victims of the Manson Family.

For the second time this year park officials plan to shut off public access to the Barker Ranch located in the Panamint Range on the west side of the park so authorities can search for human remains. Digging at the ranch is expected to get under way on May 20.

Charlie Manson and his disciplines for a time lived at the ranch before it fell within the park, and Manson was apprehended there in October 1969 after a killing spree in which actress Sharon Tate and others were brutally murdered. This past February forensic researchers found possible unmarked graves at the site that they believe could be the bodies of additional Manson victims.

Efforts to search the ranch in April failed when a piece of high-tech soil testing equipment was damaged en route to the site.