that happened twice to me this last year. the first time they broke in and tried to get the stereo but gave up because I put it in so that it takes me an hour to get out, but they did take my subs. Then exactly a month later they came back and stole my neighbors stereo and broke into my other one to take my radar detector and once again tried for the other stereo but failed, although I had to do some repair to get it to work again. now I have a nice alarm on both and I haven't had any problems. although I am suspicious that the people behind it all moved in next door shortly after the last one.