A fourth set of human remains is found at Lake Mead as the water level keeps dropping

More human remains were found at Lake Mead, according to officials Saturday.

Park rangers responded to reports of human skeletal remains uncovered at the lake's Swim Beach — the fourth set found at the lake since May.

Park rangers and the Las Vegas Metropolitan Police Department's dive team set a perimeter to recover the remains, officials said. 

The investigation is ongoing and the county's medical examiner is determining the cause of death.

Located roughly 20 miles east of Las Vegas, Lake Mead was formed by the Hoover Dam, and can hold more water than any other reservoir in the United States. 

It supplies water to millions of people.

Here's a brief timeline of human remains found in Lake Mead in recent months:

Boaters found a body inside of a barrel after extremely low water levels exposed the bottom of the lake.