Hi, Meself - I will agree that assailant is a better term, but I think that "suspect" works reasonably well.
I'm a member of the "whatever works as long as it doesn't sound stupid" school. "Suspect" is common usage, and it doesn't sound particularly stupid. I'm not bound to pedantry, but I have to admit that your choice of the word "assailant" is damn good.
-Joe-