Mystery surrounds the mid-air collision over New York’s Hudson river which claimed the lives of nine people, five of them Italian tourists.The crash was witnessed by crowds of people on the riverbanks who saw what appeared to be a light aircraft clipping the helicopter and having a wing ripped off before both fell like stones into the Hudson. “We looked up into the sky and saw something fall into the water. Then we also saw a plane minus a wing spiralling out of control. It smashed straight into the water and sank right away,” said a witness. The crash may revive longstanding criticisms of federal regulation of helicopter tours by the National Transportation Safety Board. “They have located the helicopter and it has been marked by buoys. The site has been secured by the coastguard and local authorities will be there throughout the evening. They’re using side-scanning sonar to locate the airplane and any other wreckage,” said the NTSB. A helicopter pilot refuelling on the ground saw the situation and radioed a warning to the helicopter that a fixed-wing plane was approaching behind him. There was no answer.