I am so sorry to hear about the robbery! We had that happen to us several years back. They were very selective and only took specific items, many of which would have been hard to find. We (and the police) felt it was someone who worked in our appartment complex and would have been in the appartment for inspections/maintenance reasons, since there was very little of the rest of the appartment disturbed.
I hope you manage to recover some of what you lost!