If he violates his oath of office, then he should no longer be a deputy. That's pretty important stuff. What can be done legally to discipline him, I don't know. It likely differs from state to state, possibly city to city. You would have to check with local legal authorities.
Other people asked questions on similar topics, check out the answers they received:
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them