Having opened both the shutter and the window by the three-stage method which other posters described earlier in this thread, which statistically works for a percentage of attempts, it is interesting to note that of the three stages, it is the third stage makes the greatest noise. Next consider the scenario, if having just completed the opening of window and shutter, but not having climbed in yet, the petty burglar suddemly hears and/or sees movement inside. Every petty burglar would in this scenario, for fear of getting caught, immediatley and rapidly sneak away, and would certainly not enter.
So we would see afterwards an open shutter and an open window, but with no damage, and paradoxically a bed next to the the window with no footprints, and no missing passports jewellery etc. The reason for the paradox being that the petty burglar is interupted by something, so he never enters, and takes absolutely nothing.