Yeah, I'm willing to bet most of the stuff we found in the sewers was his. Or there because of him, anyway.

[ it's okay Keith, neither does Stiles — but determination gets you far. he pauses to think for a moment, pulling up a picture of a bag of clothing: neatly folded, a variety of styles, but all in the same size. quietly thanking the powers that be for the magitek, he sends the picture to Keith. ]

See that? I found those in the sewers. All in the same size... that's a strong indication whoever put those clothes there worked alone.