"To this day, there are only about 1,200 Jews in Poland."

It seems to fluctuate between 1,200 and 1,300, but it's remained pretty steady around there since the end of WWII. I would say the most likely culprit would be a skinhead or a Tawana Brawley-type lunatic, although I find the latter rather unlikely. I would point out, however, that there is a third possibility: there are also roughly 5,500 Muslims in Poland. Although I will say that's somewhat misleading; a lot of them are Tatars, who have at least traditionally been one of the handful of Muslim groups not only not hostile but openly sympathetic to Jewish persecution (the Polish Tatars suffered pretty badly at the hands of the government in Russian-controlled Poland, especially; a few even fell victim to the same Pogroms and identified with the Polish Jews). But a recent wave of immigration from Pakistan and the Balkan states would appear to have changed that. Although the latter...the Bosniaks and the Albanians...have at least been a whole lot less anti-Semitic than one thinks of Muslims as traditionally being, the Pakistanis, at least on the whole, can make no such claim (When Pew GAP conducted a poll in Pakistan that asked "what is your view of the Jews?", 74% said either "somewhat unfavorable" or "very unfavorable." The pathetic part was that of the Muslim countries polled, that was actually second best, with Turkey's 40% favorability rating of Jews leading the way...Indonesia, Morocco, Lebanon, and Jordan also participated.). Nor can the small but significant Arab community.

A fourth possibility is a crazed militaria collector. The guy who has it all, started down the road toward not caring how he gets stuff, went into open theft, and now has to make a big leap. Before this gets dismissed as silly, my Dad prosecuted a guy who was into railroadiana so much that he stole New York City subway blueprints, pieces of railroad cars, and even an entire handcar (I think, although I'd have to check with Dad if he obtained the handcar via honest means). And don't forget some art thieves that keep their most precious/impossible to sell pieces for their own collections. There ARE crazy collectors out there (not on this site, fortunately...we're just eccentric, not insane ), and I don't think one can totally rule out the possibility.