The Body
When the party found the body they discovered the following:

• The course of death was a blow to the head from a stub weapon i.e. a club or a mace (not a rapier or knife)
• The footprints did not indicate a battle which means that victim might have known his killer.
• In the adventure the victim was earlier badly wounded in his right hand. His sword could therefore have been placed afterwards.

Footprints
Closer study of the footprints reveals a distinct mark on the killers left sole. A capitol M - maybe an initial for the murderers name?

The Boots
The party discovered that the suspect had some very compromising boots in his locker.

HOWEVER: Closer study of the boots reveals that the M is not mirrored in the snow, indicating that the most obious suspect is being framed. Who the real killer is up to the GM.