The idea that the police will take your webcam still and nail a suspect is pure yarn. Have you filed a police report when you were robbed? All the police will do is take your statement, maybe send a forensics crew to dust for prints in a day or two, and the buck stops there unless they happen upon your stuff in an unrelated incident. No manhunt is being started because your laptop was stolen.

The best piece of mind isn't a webcam and paranoia of people you don't recognize in your neighborhood, its a list of your valuables and appropriate renters/homeowners insurance to replace whatever might have been stolen.