A fifth set of human remains has been found in Lake Mead in the south-west US, exposed as water levels have fallen due to drought.
Several sets of human bones have been discovered in the lake in the past couple of months, as levels have declined.
The most recent set of remains at Lake Mead, which is off the Colorado River in the states of Arizona and Nevada, were found on Monday, the National Park Service said.
"The investigation is ongoing," the service said.
The first remains were discovered in May inside a barrel. Investigators said the remains were most probably of a man who was killed by a gunshot and dumped into Lake Mead four to five decades ago.
"It's likely that we will find additional bodies that have been dumped in Lake Mead," Las Vegas homicide detective Lt Ray Spencer said at the time.
A second and third set of remains were found over summer. Another set of bones were found last week.
None of the remains have been identified or linked to any individuals in the ongoing investigations.
The discoveries have prompted speculation about long-unsolved missing people and murder cases from decades ago — to organised crime and the early days of Las Vegas, which is only a 30-minute drive from the lake.
The lake surface has dropped more than 50 metres since the reservoir was full in 1983.
The drop in the lake level comes as most scientists say the world is warming mainly because of rising levels of carbon dioxide and other greenhouse gases in the atmosphere.
Scientists say the US west, including the Colorado River basin, has become warmer and drier in the past 30 years, and led to drastic water cuts.
Sunken Second World War landing craft revealed as Lake Mead dries up - in pictures
News agencies contributed to this report
