The 34-year-old man who went missing off Northland's Uretiti Beach yesterday is presumed to have drowned.
Alexy Ivanov of Auckland was last seen entering the water about 5pm.
Department of Conservation staff at a campground alerted police after they noticed his clothing and car had not been touched an hourlater.
A search of the area lasted until dark yesterday and continued this morning, including a helicopter covering the area around where Mr Ivanov went missing.
Algae bloom made visibility difficult, said police.
The boys went into the water at Promenade Point on Lake Taharoa about 6.30pm and swam out to the end of a shallow shelf of water. The boy who drowned remained in the shallow water while the other three boys swam across a small canal to the other side of the lake.
When they returned a short time later they noticed the other boy was not there and found shirt near the lake edge, so they started looking for him.
They discovered him lying four metres below the surface of the water and pulled him out. The boys started CPR on the deceased boy before the ambulance arrived. However, he died at the scene.
