Three large tiger sharks forced a search team to halt its efforts yesterday to locate and recover the body of a missing swimmer from Northern California who had disappeared from Laniākea Beach Tuesday evening.

The Honolulu Fire Department's Air 1 helicopter spotted the sharks about 7:30 a.m. near a body that was floating roughly a half mile off Pāpa'iloa Beach (approximately 1.5 miles in the Hale'iwa direction from Laniākea), said Honolulu fire Capt. Terry Seelig.

"The body ... was surrounded by three large sharks and they were behaving in an aggressive manner," Seelig said. "Then the body disappeared. We lost sight of the body."

At that point the lifeguards issued a shark warning and closed all beaches within one mile of the area, he said.

Following ocean safety protocol, the fire department would not allow its rescue divers in the water for a 24-hour period. But the air search continued, Seelig said.

The Visitor Aloha Society of Hawai'i is helping the swimmer's wife of six years and his family. Visitor Aloha Society of Hawai'i officials described the swimmer as a 35-year-old man from Beijing who was living in Sunnyvale, Calif.

Other family members will arrive from Beijing on Saturday, VASH officials said.

"The visitor's family would like to express their thanks to all emergency teams who have dedicated their time and energy in the search efforts," VASH officials said in a statement.

Helicopter pilots described the animals around the swimmer as 12- to 15-foot-long tiger sharks, said Bryan Cheplic, spokesman for the city Emergency Services Department.

It was not the first time the body was spotted.

Tuesday night, HFD helicopter crews and the Coast Guard spotted what appeared to be a body in the water just before dark off Laniākea. Rescue divers were dispatched but were unable to find the body because of the breaking surf and nightfall, Seelig said.

"They couldn't get to the location before it disappeared from view of the helicopter," Seelig said.

Yesterday morning rescue workers were walking the beach at 6 a.m. and the helicopter returned at 6:30, spotting the body at 7:30, Seelig said.

"The body we saw in the water had no visible signs of life so this is now being considered a recovery effort rather than a rescue," he said.