If you want to be a bit of a rat-bastard:
The wizard is apprehended in front of the PCs (by Maruts sounds pretty cool). Just when the situation seems to be resolved (either by negotiation, combat etc.) he then melts into a mound of snow (Simulacrum).
The Maruts then attempt to press the PCs to hunt down the real wizard. Kind of a sharp reminder that their dealing with powerful individuals on every side - with access to way too many resources.
That's cool.