A shark attacked and killed a swimmer training with a triathletes from the Triathlon Club of San Diego at 7 a.m. Friday morning off Tide Beach in San Diego County, California. Dave Martin, 66, was bitten across the legs by what is believed to be a great white shark. He was taken to Fletcher Cove Park lifeguard station for emergency assistance but was pronounced dead at the scene. Swimmers were ordered out of the water within a 17-mile radius of the attack for the next 72 hours, as the shark is still in the area.