Ouch! That's a nasty one. He will have insurance but I guess that's not the point. Hopefully the thief will be caught trying to palm off stuff he has no idea about. Doesn't seem like a "stolen to prder" job or they would have taken the briefcase as well.
Suggestion is not already done. could you start a topic for items of thief, so if your ever at a show or on craigslist and see this example and instead of try to find it, you could go straight to a topic/form for stolen or lost and maybe just to keep it simple just pot the new report along with the photo of his writing (describing the stamp and price label)