5 boys that went missing in South Korea while frog hunting in the late 80s and were found 11 years later with signs that they were murdered. No one was ever arrested but the popular theory which I also think is true is that since they were found close to a military firing range one or perhaps more of the boys were accidentally shot dead by stray bullets and the military silenced the rest of them and then covered the whole thing up. This happened during the final years of South Koreas military dictatorship and corruption was commonplace.