Well, I was wondering why they didn't take the amps? Did they try? Because if they pulled them somehow, I would imagine, they strecthed the wire, allowing it to rub or cut the wire somewhere or on something. It would be your red wire or (+) comming from your battery.I would look for any cuts along here where you would think it could rub against something.
If not, it could be just a bad amp. Was the amp working before the break-in? Sometimes its hard to hear, lol. Also, if somehow water has enter in it, that could be another cause. Or maybe somehow it could be the wiring of your subs *ohms*. not sure though.
Purpose of Fuses:
The purpose of a fuse is to open *blow* an electronic circuit when current flow exceeds a certain amount, determined by the rating of the fuse. Opening *blowing* a circuit under high current conditions can save electronic components from damaged and prevents overheating, which could cause a fire.
Hope that helps