A great white shark killed an American diver Saturday in the second fatal shark attack off Western Australia state in 12 days. A witness on a dive boat saw “a large amount of bubbles” before the 32-year-old man surfaced with obviously fatal injuries, Western Australia Police Sgt. Gerry Cassidy said. Two people on the boat described the shark as a 10-foot (3-meter) great white, Cassidy said. The shark struck 500 yards (meters) north of the picturesque tourist haven of Rottnest Island which is 11 miles (18 kilometers) from a popular Perth city mainland beach where a 64-year-old swimmer is believed to have been taken by a great white on Oct. 10. The American was living in Perth on a work visa. Police would not release his identity or hometown. Authorities cannot say whether he was killed by the same shark that is believed to have taken Bryn Martin as he made his regular morning swim from Perth’s premier Cottesloe Beach toward a buoy about 380 yards (350 meters) offshore. But analysis of Martin’s torn swimming trunks recovered from the seabed near the buoy pointed to a great white shark of the same size being the culprit. No other trace of Martin has been found. “It’s a cloudy old day today which is the same as we had the other day with Cottesloe, and they’re the conditions that sharks love,” Cassidy said. It is the fourth fatal shark attack off Western Australia in 14 months. Great whites can grow to more than 20 feet long (6 meters) and 5,000 pounds (2,300 kilos). They are protected in Australia, a primary location for the species.