Over the years since Poe died, people have started coming up with theories of how he died, from alcohol poisoning to murder. A popular theory that people came up with is cooping. Cooping is a method that was practiced by 19th century gang members. The gang members kidnap an unsuspecting bystander, disguised and forced them to vote for a specific candidate multiple times, under multiple disguised identities. The victims were often given alcohol as a reward for following instruction.
Taking in to consideration that Poe was wearing clothes that were not his own and he was sort of out of it, I think this is the best theory to explain his death. Also, Joseph Walker found a disheveled Poe wandering the streets