MARATHON, Fla. -

State wildlife authorities thought a Marathon man had dumped a body in the water after hearing a gunshot on a boat in Boot Key Harbor. Instead, they found a dead dog in the water and an intoxicated man who fired the shot on the boat.

Kevin Sullivan, 35, was arrested Tuesday on suspicion of using a firearm while under the influence of alcohol.

According to a Florida Fish and Wildlife Conservation Commission report, two officers were on patrol Tuesday night when they heard a gunshot coming from a boat without any navigation lights and then "saw a large object go over the bow of the vessel into the water."

Thinking the people onboard may have dumped a body, the officers conducted a boat stop.

Sullivan, who was a passenger on the boat, appeared intoxicated and his breath smelled of alcohol, the report said. Officers said the boat's operator was not impaired.

A third officer arrived and searched the area, finding a dead dog surrounded by a pool of blood. Officers said the dog didn't appear to have any wounds consistent with a gunshot, but it appeared the dog had been run over by the boat.

When officers questioned the men about what they dumped, they claimed they hadn't dumped anything. Officers then asked them what happened to their dog, and that's when they realized the dog wasn't on the boat.

The boat's operator told officers that he and Sullivan "had gone offshore to shoot some rounds" and Sullivan fired a final shot on their way back. He explained that his dog was afraid of loud noises and the gunshot must have scared off the dog.

When asked if he had been drinking, Sullivan said yes and told officers he was "a heavy drinker," the report said.