BERKELEY (CBS SF) — Crews clearing a drainage ditch at the Lawrence Berkeley Lab found a human skull and three human bones.

The gruesome discovery happened the afternoon of April 18th in an area of steep brush on the southern perimeter of the facility, according to Berkeleyside.

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The Alameda County Coroner was examining the bones.

It is not clear how long the remains have been in the ditch, but foul play is not suspected.

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Sgt. Paul Graves said Monday forensic pathologists have still not identified the person’s sex or determined how long the bones had been in the ditch.

He says the bones were not believed to be those of an American Indian.

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Officials say the coroner’s office may contract with an anthropologist to help determine the age of the bones and the circumstances of the death.