The movie "The Brutal River" 2005

In the 1960s, there were few places on Earth as quiet and peaceful as Thailand's Chumporn province, where life went on as it always had. This tranquility is shattered the day an unidentified body is found on the bank of a stream. Before long, the villagers begin to disappear mysteriously. Locals struggle to find out the cause of the disappearances and who the dead stranger is. While trying to track down the killer, they find strange tracks that could only have been made by some kind of huge animal...