Human remains in a barrel were discovered Sunday along the drought-parched and receding shoreline of Nevada's Lake Mead, police said.
The National Park Service alerted Las Vegas police about the discovery.
Investigators believe the victim was killed in the 1970s or the 1980s based on the clothes and shoes found on the body, Las Vegas police said in a statement.
“We believe this is a homicide as a result of a gunshot wound,” Homicide Section Lt. Ray Spencer said, according to the statement.
The Clark County medical examiner will work to confirm the cause of death, the National Park Service said.
The National Park Service added in a statement that rangers first investigated the incident at Lake Mead National Recreation Area on Sunday afternoon. The investigation continues, and the Park Service declined to comment further.
Lake Mead's historically low water levels last month exposed a water intake valve that had been serving Las Vegas-area customers since 1971.
Lake Mead and Lake Powell upstream are the largest human-made reservoirs in the U.S., part of a system that provides water to more than 40 million people, tribes, agriculture and industry in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming and across the southern border in Mexico.