About 75 law enforcement officers from at least four agencies are searching on land, under water and by air this morning for the body of a Raleigh man who disappeared Friday night in Lake Gaston, authorities said.

Authorities have been searching for Karl Besas, 24, of Raleigh since Friday night when he never returned to a boat from which he and four friends dived to go swimming.

The friends called 911 when Besas failed to reappear.

Units from Smith Mountain Lake, Va., and the the Norfolk, Va., police harbor patrol have been called in today, said Halifax County Sheriff's Capt. Jay Burch.

After divers' attempts to find the body were unsuccessful over the weekend, Burch said sonar equipment is being brought in to look for Besas.

The state Highway Patrol has also launched aircraft to search over the lake, Burch said.