A $15,000 reward is being offered to find three shotgun-toting vandals who broke into a habitat at Death Valley National Park, leaving behind a trail of beer cans, vomit, shotgun shells and a pair of boxer shorts in an ancient, water-filled cavern where officials discovered an endangered fish dead.

On April 30, three men in an off-highway vehicle pulled up to a gate at Devils Hole and opened fire on two locks and several signs, before going swimming in the cavern — the only natural habitat of the critically endangered Devils Hole pupfish, Death Valley officials said.

One surveillance camera captured the men bumping into the gate with the vehicle. In another shot, the vandals are inside the gated area, where one of them appears to urinate. An underwater camera shows one of them stepping into the murky waters.

Two days later, park employees found a pupfish dead, and one of the men’s boxer shorts in the pool.

"Devil's Hole pupfish have been teetering on the brink of extinction for years. The last thing they need are these idiots running amok in the last place on Earth where they still survive," said Ileene Anderson, a senior scientist with the Center for Biological Diversity.

The men had also allegedly tried to disable the security system by shooting at a motion sensor and removing cables from two cameras, but officials said part of the system continued to function and recorded the vandals climbing over the fence and driving away in what appeared to be a heavily customized blue Yahama Rhino.

The men fired at least 10 rounds with a shotgun, park spokeswoman Abby Wines said.

The results of a necropsy to help investigators determine whether the men were responsible for the pupfish’s death were pending, Wines said.

A reward is being offered for an arrest and conviction in the case - $5,000 from the National Park Service and a $10,000 increase Monday from the Center for Biological Diversity. Anyone with information was asked to call park investigators at 888-653-0009.

The Devils Hole pupfish has been isolated 10,000 to 20,000 years at the Devils Hole in the Ash Meadows National Wildlife Refuge, an area of desert uplands on the Nevada side of Death Valley National Park. The population has been in severe decline since the mid-1990s, according to the National Park Service. At last count, 115 pupfish were spotted in the waters.