That's an interesting question. I'd be interested to know the answer to that too. From messing around with it right now, it seems to work if you play in D over it, and F# seems to be the tonal center for a lot of it, with the 4th being sharped in the chorus. That doesn't make it any more clear to me, so I'm hoping one of the theory-heads will pop in and see if they can make sense of it. Right now my unofficial guess is that the song is in F# phrygian.