Authorities euthanized a 13ft alligator with human remains in its mouth after the animal turned up on Friday afternoon in a canal in Largo, Florida.

The Pinellas county sheriff’s office said in a news release that the male alligator measured 13ft 8.5in and was “humanely” killed after being removed from the water. The sheriff’s dive team recovered the human remains from the waterway.

Deputies stopped short of saying whether investigators believed the alligator had killed the person whose remains were in the animal’s mouth.

Deadly alligator attacks are rare. According to the online animal encylopedia AZ Animals, there are an average of about six fatal alligator attacks reported in the US each year.

More than 1 million alligators reside in Florida. Over the last 10 years, Florida has annually averaged about eight unprovoked alligator bites on people that have warranted medical attention.

Jamarcus Bullard described spotting the alligator on Friday afternoon in remarks to a local NBC News affiliate.

“I threw a rock at the gator just to see if it was really a gator and like it pulled the body – like it was holding on to the lower part of the torso and pulled it under the water,” he said. Bullard then recorded the alligator with his cellphone and provided it to authorities.

Investigators said they were conducting an autopsy of the person whose remains were found with the alligator to determine a cause of death. The identity of the dead person had also not been established, according to officials.