I do sympathize that police deal with liars, scammers, and scum constantly, and this can color their thoughts, perceptions, and actions.
However, our system of justice is predicated on the idea that it must avoid prosecution of the innocent at all costs, up to and including allowing the guilty to go free. For "government" in all it's myriad forms has killed, enslaved, and harmed orders of magnitude more people than "crime" ever has.