A man swimming in a muddy Australian river was attacked and killed by a giant crocodile on Saturday. The gruesome attack was witnessed by 15 of the man's friends, who were camping along the river to celebrate another friend's 30th birthday.

Sean Cole, 24, was swimming with a friend in the Mary River at the Mary River Wilderness Retreat when the crocodile attacked and dragged him beneath the water.

"Several of the group in the party witnessed the male being taken in the jaws of the croc for a period of time, and then he was out of sight," Senior Sergeant Geoff Bahnert told the Associated Press. "The Mary River is known worldwide to have the greatest saturation of adult saltwater crocodiles in the world. You don't swim in the Mary River.”

Police and a government crocodile team arrived at the river Saturday evening. Witnesses described hearing gunfire late into the night as authorities hunted the killer croc. One of the area's larger crocodiles was killed, though it wasn't immediately clear if it was the one that killed Cole.

Campers at the wilderness retreat reported seeing a 15-foot crocodile resting on the river's opposite bank earlier that afternoon.

“I would never go in that water,” camper Eric Linhart told NT News. “Why that young man did I don't know.”

Bahnert said alcohol may have played a role in the incident.

[Image via Shutterstock]