If you have always wanted to be a police officer since you were a little kid, then tell them that. Of course, what they really want to know is specifically why do you want to go into law enforcement? If you tell them you want to kick butt and arrest people, you will not pass the interview. Tell them what it is about law enforcement you find attractive. Maybe you like investigative work and would enjoy the challenge of trying to figure out what happened or who did it. Emphasize the high moral standards you have. Protecting your community is something you would like to do.

The panel may also ask why you want a job with their specific agency or department. Do not tell them you always wanted a job with them. Do not tell them they are the best agency even if you feel that way. They will not view your answer as sincere. To them, it looks like you are saying whatever you need to say to get the job. In this case, flattery will get you nowhere. You should tell them what you like about their agency. If you have heard good things about their department, then tell them that. If you know someone who works for them, you can probably mention their name. Tell them that this person had good things to say about them. Be honest but do not try to snowball them. After all, these are police officers that are interviewing you.