Federal investigators with the National Oceanic and Atmospheric Administration are offering a reward of up to $20,000 for information leading to the arrest and prosecution of a person seen decapitating a sea lion on Christmas Day last year.

A $20,000 reward is being offered for information on a grisly discovery at Doran Regional Park in Bodega Bay on Christmas Day. NOAA’s Office of Law Enforcement is investigating after a man was reported to be seen cutting the head off of a California sea lion.

The suspect was seen using an 8-inch black knife to remove the sea lion’s head, placing it in a clear plastic bag, and riding away, authorities said.