Well you can always expect the police to stand with one of their own. After all, think of coworker relationships in any unionized workplace. You've got "the guys" and "the bosses." When you also take into consideration that people with law enforcement degrees typically only have one potential employer in town, it's obvious that "the guys" are going to look out for one another.
So it's no wonder why the local PD initially tried to throw the book at him.