A Great White shark has killed a US diver in what is thought to be the second fatal shark attack off western Australia in 12 days. The diver, 32, who has not been named, was diving alone off Rottnest Island near Perth on Saturday. Witnesses on his boat saw a large amount of bubbles surfacing, followed by the diver's body which police said had obviously fatal injuries. Two people on the boat described the shark as a 3-metre (10ft) Great White. Sharks attack more often in cloudy weather and police said the day had been overcast. The man's name and hometown have not been released, but authorities said he was living in Australia on a working visa. Fourth recent attack The death of the diver comes days after the disappearance of Bryn Martin, a 64-year-old businessman, last seen 350m from shore at Perth's Cottesloe Beach on 10 October. His swimming trunks were later found on the sea floor, with damage said to be consistent with a shark attack. Last month, 21-year-old bodyboarder Kyle Burden was killed near Bunker Bay, 260km south of Perth. In August last year, surfer Nicholas Edwards, 31, was killed by a shark at a popular surf break in nearby Gracetown. Sharks are a common feature of Australian waters but, according to the Australian Shark Attack File, attacks are rare with only 53 fatalities in the last half-century.