This brings me back to when I got my DS case stolen/taken/picked up. My DS was not in it, but my CycloDS MicroSD adapter was. I was so upset. It happened at school, and I either dropped it by my locker (I had a bottom locker that year) or in the hallway. Probably by my locker because I rushed to school. By the time I realized it was gone, at least three hours had passed. Other than that, I haven't had anything stolen. Now I am overprotective about my things. I don't even let my friends use my DS sometimes. I had to buy a new case, and a new MicroSD adapter. Luckily I found cheap ones. >$3 CAD for the case, and $5 CAD for a multi-card reader.
Yeah that bites... getting your Pandora stolen, especially when you waited so long for it. This also reminds me of when my brother lost my GameBoy Advance SP.
My suggestion: pour laxatives in the new guy's coffee/tea, then when he makes a run for it, raid his stuff. Then track down his house and raid there.