Yeah he's a nut-case and should've been arrested for a surplus of things, but "impersonating an officer" is an abuse of power on the police's part. He can say what he wants, unless he has a badge, etc, literally claiming to be one and use "police power" he was not abusing an officer
He claimed to be famous and that Katy Perry was his wife before offering police sexual favors in exchange for his release. He also said that he had wreaked havoc in the mall because he did not have a winter coat.