I have an idea! This may be able to explain his rapid decomposition and messed up face. According to the Chicago tribune, he was lifted among other debris and fell out, he had been there for some time before he was reported, so perhaps that explains it? And more importantly did anyone see the body and fail to report it, and could they be involved in the mob? Also to further elaborate the reason he had such rapid decomposition is when you are taken out of water your body decomposes faster, and he had more exposure to the elements for some time.