A fisherman found a partial human jawbone along the Waimanalo shoreline over the weekend, police said.

The fisherman was looking for starfish near the Makai Research Pier at about 3:15 p.m. Saturday when he stumbled upon the bone under a coral rock, police said.

Officers retrieved the jawbone and turned it over to the Honolulu Medical Examiner’s office for investigation.

Police also notified the State Historic Preservation Division at the Department of Land and Natural Resources, which will contact the Medical Examiner’s office to determine whether the bone is more than 50 years old.

Russell Soriano, head of security for the pier, said police spent at least two hours at the beach investigating the discovery.

He said the bone was found behind a row of coral rock along the shoreline, beside a sandy area adjacent to the Makapuu side of the pier. On Sunday, beach goers sat on the sand just feet away from the same coral rock.

“This beach is so busy I don’t know how that thing got there,” Soriano said before recalling that king tides had came in a week prior. He suspected they could have washed the bone up onshore.

Stephanie Park, who was visiting from Washington D.C., was picking up plastic on the beach Sunday when she was told about the fisherman’s find.

“It’s a grisly discovery,” she said.