This question gets asked what... every couple of days, "I have a crime on my background and want to become a police officer." The answer is always the same.
When you choose to commit a crime, you put yourself at a disadvantage as compared to applicants who don't have criminal records. It's up to an individual police department to decide whether or not to hire you despite your record, but it's something that can be counted against you when you're being compared to similarly credentialed applicants.

