Federal wildlife authorities have opened an investigation into a grisly discovery on a Jersey Shore beach: the partial remains of a dolphin that, according to a marine animal rescue group, “appeared to have been butchered.”

The National Oceanic and Atmospheric Administration’s law enforcement division is investigating the death of the dolphin, whose carcass was found last Wednesday, an agency spokeswoman said on Tuesday. She declined to comment further.

The investigation began after the Marine Mammal Stranding Center, a rescue, rehabilitation and release organization in Brigantine, N.J., received what it described in a social media post as a “very disturbing call.” Partial dolphin remains, the group wrote, had been discovered on the beach in Allenhurst, just north of Asbury Park.

“When our stranding coordinator arrived,” the group wrote, “he found a common dolphin that appeared to have been butchered. The animal’s flesh had been completely removed with clean cuts from a sharp instrument, leaving only the head, dorsal fin and flukes. The animal’s organs, except for the heart and lungs, had been removed.”

The common dolphin is not endangered or threatened in the United States, according to NOAA, but it is protected under the Marine Mammal Protection Act.

With some exceptions, the act prohibits the “take” of marine mammals, which is defined as the harassment, hunting, capturing, collecting or killing of the animals in U.S. waters or by U.S. citizens on the high seas. Violations can be prosecuted civilly or criminally and are punishable by up to $100,000 in fines and up to a year in jail for each violation.