INVERNESS, Scotland (Reuters) - An amateur photographer who snapped mysterious happenings in Scotland's Loch Ness has puzzled experts and led to renewed speculation about the existence of the monster said to live in the lake. Scottish pet food salesman Richard White noticed something strange in the loch as he drove along its eastern bank and realized it could be the elusive "Nessie." "I always carry a camera in my van in case of a road accident," the former soldier told a Scottish news agency on Monday. "I was on my way to Foyers, a small village above the loch, as part of a regular sales run, when I noticed an unusual disturbance halfway across the loch toward Urquhart Castle on the opposite bank. "I stopped to take a look and remembered I had the camera, so I got it out and just started reeling off the photos," he said. White, 53, has been awarded 500 pounds ($825) by a firm of British bookmakers which offers a prize for the best "Nessie" image of the year. Sightings of the mysterious monster, often described as having a long neck and a large body like a brontosaurus, have been reported since the 15th century. Around two million tourists flock to the murky loch each year hoping to get a glimpse of the beast. "This is a remarkable sequence, some of the best 'Nessie' photos that I have ever seen," said Gary Campbell, president of the Official Loch Ness Monster Fan Club. White and Campbell did not want to go public until the pictures had been analyzed by scientists using computer enhancement techniques. Campbell said the fact that experts had been unable to decide exactly what the pictures showed only added to the mystery of the Loch Ness monster. "With so many of the photos taken of 'something' in Loch turning out to be a boat's wake or some other everyday object, it is great to have a real mystery on our hands," he said. In February last year, a Scottish auxiliary coast guard officer said he had found the monster's secret lair on the bottom of the 23-mile (37-km) long loch.