FORSYTH COUNTY, Ga. — Crews from the Georgia Department of Natural Resources began a third day searching for the body of a 28-year-old boater from Atlanta at 6 a.m. Sunday. He had been missing since Friday evening.

Game wardens were initially called to the scene of a possible drowning offshore in Lake Lanier near the Vann's Tavern Park area in Forsyth County at about 6:15 p.m. Friday.

According to Sgt. Lee Brown with the DNR, a number of people were on board what he described as a double-decker pontoon boat that had a slide. The people were using the slide to go swimming in the lake.

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Sgt. Brown said one of the people using the slide needed some help, and that the victim -- later identified as 28-year-old Corey Lamar Brown from Atlanta -- jumped into the water to try to help. Sgt. Brown said that Brown began to struggle as well.

Sgt. Brown said that Brown did not have a life jacket on when he jumped into the water.

When game wardens arrived, they were able to two others from the water.

Sgt. Brown says that Brown may have become fatigued or experienced shock due to the temperature of the water. 

According to the US Geological Survey, the water temperature of the lake can vary widely, with surface temperatures as warm as the high 70s near shore or as low as the low 60s in areas along the Chattahoochee River just below Buford Dam.

DNR Public Affairs Officer Mark McKinnon told 11Alive that everyone should have a life jacket when boating. 

"Where they can get it -- not in a storage locker, not in a bag," McKinnon said. "When you're on the boat, make sure you have one for everyone on board -- and that especially everyone who is under 13 has those life jackets on."

Friday night's search was called off after sundown.

Saturday morning, crews resumed their search, which quickly shifted from rescue to recovery mode.

DNR Public Affairs Officer Mark McKinnon said that crews on both days were using sonar equipment to help discern whether or not they could find Brown in the water. On Saturday, game wardens used sonar through the morning and afternoon hours.

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DNR Aviation flew the area around the midday hours. Hall County search teams also had divers in the water assisting in the search.

McKinnon said that when boat traffic in the area got heavy in the afternoon hours, the search was scaled back to surface searches, which continued into the evening hours.

According to McKinnon, the plans for Sunday are more of the same. Game wardens with sonar and divers in the water will be used until boat traffic in the area gets too heavy, then they will continue with surface searches.

He said DNR Aviation will fly the area again if the weather permits.

McKinnon says that along with the heavy boat traffic on the lake, an additional difficulty is that the terrain on the lake bottom. It is very rugged, with numerous large rocks. The bottom also varies in that area, running anywhere from 8 feet deep, down to 50 feet deep.