Hmmm,
Physically robbing a bank might not be such a good idea as Rust has already said, but we could make it so that the criminal can only do it once every few hours/days etc. and that the criminal loses all the moeny if he's caught. but then again, this won't work as people will just come online to rob a bank and leave before the police catch him and continue to do so till they can get their dream house etc!

This would be abusing the RP. So, we better leave it for RP at the moment.
Robbing a car? Well, that's mainly RP. You could pretend to hotwire the car if you wish and smash the glass to get in

.
You were talking about stealing weapons and money. Weapons, well they get dropped when someone dies or there is the Ammunition shop. But about the money, it gives me an idea. We could have a "pickpocket" feature. Criminals could attempt to pickpocket in both RP and physically and the cops could track them down.