Koh Tao--a small island in the Gulf of Thailand, surrounded by pristine beaches, swathed in sunshine, and a mecca for tourists, divers and backpackers. But "Turtle Island" has its dark side. In 2014, Koh Tao was the site of the brutal double murders of two British backpackers, but theirs weren't the only suspicious backpacker deaths. My name is Suzanne Buchanan. I am the former owner and editor of the Samui Times, a news publication...