Oh man, if this happened where I worked, you would both be out of a job so fast. Especially trying to impersonate a police officer and scare you. Here is the issue though, what he did caused no harm to your property aside from being irritated or scared etc. You actually ruined his lunch. There's a difference. Of course it's not necessarily fair because he escalated it, but unplugging your USB, taping your receiver and sharing you as a cop, is not the same as freezing his lunch for the day no?
If I were you, and you guys are good friends, I'd approach him in person, apologize, ask him to lunch one day as a way of saying sorry, and then also tell him he went over the line with what he did too. And then end this prank Vs. prank stuff, you're not children and it's escalating to where you both don't appreciate it.