A 38-year-old Las Vegas man who went missing on Lake Mead on May 31 is presumed dead after the National Park Service and Nevada Department of Wildlife failed to locate his body.

A second man died from an apparent heart attack while jet skiing on the lake Saturday.

The search for the 38-year-old, which was suspended after a night and two days, involved park rangers searching for the man on the surface of the lake and shore, and the department of wildlife searching for him on the bottom of the lake with SONAR, park service spokesman Andrew Munoz said.

Munoz said divers were not sent to look for the man’s body because the SONAR revealed nothing in the 100-foot depths. To send divers in would have been dangerous, he said.

“Diving itself poses risks, especially in those areas in those depths,” he said.

The man went missing after he jumped into the water to assist two other men with an inflatable raft, and in the high winds became separated from both the men and the boat he was driving.

On Saturday, a 51-year-old Colorado man died two hours after he apparently had a heart attack while riding a jet ski on Lake Mead.

There have been five deaths at Lake Mead National Recreation Area this year, Munoz said. - Jack Johnson