NEW YORK (CBSNewYork/AP) — An investigation is underway in Brooklyn after a construction crew unearthed skeletal remains at a dig site near a psychiatric hospital.

Workers were doing sewer repair work at the East Flatbush construction site when they found a skull, arm and leg bones 13 feet below the surface Monday afternoon, police said.

The city medical examiner later confirmed the remains found at the Clarkson Avenue site belonged to a human.

Authorities do not know how long the bones had been there.

“Right now we think this is a disinterment of a burial,” Chief of Detectives Robert Boyce said, adding foul play is not suspected. “This looks like they’re old bones but we’ll go forward through forensic anthropology.”

The construction site is near the Kingsboro Psychiatric Center.

Police continue to investigate.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)

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