Authorities are investigating the circumstances surrounding a mutilated dolphin found dead on a New Jersey beach last week.

The animal, a common bottlenose dolphin, appeared to have been “butchered” when “partial remains” washed up on an Allenhurst beach on Wednesday, according to a Statement from the Marine Mammal Stranding Center on Fridaya federally licensed marine mammal rescue, rehabilitation and release organization in New Jersey.

“The flesh of the animal were completely removed with clean cuts from a sharp instrument, leaving only the head, dorsal fin and flukes,” the statement said. “The animal’s organs, except for the heart and lungs, were removed.”

The National Oceanic and Atmospheric Administration is investigating, according to the stranding center.

The night before the gruesome discovery, a common bottlenose dolphin was said to have been struggling in the surf a block away, according to the stranding center. Witnesses said the dolphin managed to get over a sandbar and swam out to sea. It is not known if the dolphin that was slaughtered was the same animal, the stranding center said.

The animal’s carcass was taken to the stranding center and “thoroughly” photographed and documented, the group said.

The remains were buried on the beach, the stranding center said.

Allenhurst is about 45 miles east of Princeton, New Jersey.