Gnomes

Does anybody know of an effective way to trap gnomes? My apartment seems to have a rather bad infestation. I haven’t seen them so far, but just this week several things have gone missing. An MP3 player and my wallet being the big ones, but any random thing I’ve happened to be looking for has been curiously absent as well. The MP3 player could have been lost anywhere, but the wallet was never taken out of the apartment — I haven’t been using the purse it fits into, and have been taking the cards out and putting them loose into my smaller purse (at least that means I didn’t lose anything important IN the wallet). There haven’t been any shady or unsupervised people in the apartment, and besides, what would anyone want with a bottle of Lysol, a spool of black thread, some pink barrettes, or a couple of 18g needles? It could only be gnomes. I’m convinced of it. I’m not one of those people that misplaces things. The table beside our bed, the desk, and the bathroom closet all look like tornadoes hit them, but I know exactly what’s there, and exactly where it is. So now I need to capture and torture these gnomes, and get them to give my stuff back. Advice, please.