Here is what I think, His gf went missing on june. He found out something about her had a fight with some guy who was obviously guilty for something which resulted in this. Or He kidnapped his girlfriend, someone tried to save her and he killed him
The man was seen drinking a LOT that day. People usually drink to num there senses. Which means either he was in tension or he was scared.Considering the fact that he had a human hand with him it was obviously fear. So a scared white man drinking..