Be the first to answer this question and get 10 points !!!!!!TODAY!!!!!!!?

the police found a dead man hanging from the rafters of a seventy five foot tall and twenty five foot wide empty grain silo...there is no windows in the silo and no holes in the roof..... the only door was locked from the inside, and there was not a piece of furniture or anything to stand on,the rope that he used to hang himself with was only five feet long.......(clues)!!!! the only thing that they found when they got there was a 18 wheeler on the outside, and when they busted the door down they saw a puddle of water!!......"how did he hang himself"