On Sunday June 5th 1960, at Finland's scenic Lake Bodom, the sun had risen at 4:04 AM. By 11:00 AM the heat of the day had already set in and carpenter Esko Johannson and his son were ready for a swim. While floating along happily the pair noticed something strange on the Lake's far shore. A tent appeared to be laying trampled on the ground. Esko went to investigate, and upon further inspection realized the the little campsite was soaked in blood and four bodies lay tangled in the fallen canvas of the tent. The investigation that followed uncovered one of the most baffling mysteries in Finnish true crime history. Before Sleepaway Camp, Before Friday the 13th, Before AHS 1984, there was Lake Bodom. What makes this story the most frightening entry in the summer camp murder cannon, is that it's all true. 

Further reading. Some details are hazy due to the translation

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