Sanitation workers made a grim find along Brooklyn’s Belt Parkway on Friday afternoon — a skull and bones mixed in with a pile of trash, police sources said.

The Department of Transportation workers were making a pick-up from a construction area in the westbound lane of the highway near Exit 11 N at Flatbush Avenue around 3:45 p.m. when a skull tumbled out of one of the bags, sources said.

A number of bones were also found inside the bag, sources said.

NYPD investigators headed to the site to set up a crime scene, as the skeletal remains were sent for testing to determine if they’re human.