You'll be asked questions concerning your integrity:
For example, the panel may ask you what would you do if you caught a fellow police officer stealing.
You'll be asked questions about your motivation:
For example, the board members will ask you why do you want to become a police officer? What's your motives behind it.
I suggest getting a police oral interview prep guide. I used one and it helped me pass my interview. You can get one at www.policeoralboardinterviewsecrets.com