The man, Jamarcus Bullard, tells NBC News he saw the alligator and a body in the water Friday afternoon.
“I threw a rock at the alligator to see if it was really an alligator and it kind of pulled the body, it kind of held the lower part of the torso, and pulled it under the water,” he says.
Bullard filmed the alligator with his cell phone and then contacted authorities.
The alligator, which was male, was removed from the canal and “humanely euthanized,” according to local police. The remains of an adult person were recovered.
Authorities have not released details about the victim and an investigation is ongoing.