Authorities will head back  to Lake Lanier Monday to search for a 44-year-old man is believed to have drowned.

44-year-old Jeffrey Nause was last seen just after midnight Saturday morning when he jumped off a sailboat near Lake Lanier Islands. Three others were on the boat. They say Nause was having trouble in the water and then disappeared.

“After interviewing witnesses, no one actually saw him go underwater,” Sgt. Mike Burgamy with the Department of Natural Resources told Channel 2 Action News. “They heard him (and) lost voice contact with him.”

Search teams hope to bring in more equipment when they head back out to the lake on Monday.  

Crews started to use side-scan sonar equipment underwater to get a better idea of the terrain and where the body might be. But the search teams had to call things off when heavy boating traffic made things too dangerous.

“The boat traffic has really picked up and it’s really difficult to run the side-scan with waves coming in,” said Burgamy.

Authorities also went out about four hours Saturday afternoon trying to find the body. They it is in an area that is thick with timber, about 70-140 feet deep.

The case is being investigated as an accidental drowning, authorities said. It would be the 11^th drowning in Lake Lanier this year.

Nause’s brother-in-law and nephew also spent hours roaming the lake themselves, while crews searched for his body.

His brother says Nause was a Georgia Tech graduate, CEO of a semi-conductor business and  is the father of two children.