Murder, she wrote part 2

The investigation has begun!  Two police detectives are perusing the crime scene:

Nothing has been altered yet, although the corpse has been removed, and the silhoutte of the deceased has been marked in the ground - the blood puddle is still fresh...  The detectives are currently searching for clues.  Notice the magnifying glass in the hand of one of them:

The other one is searching through the papers.  Is the murder related to the dead man business?  Who knows?  Better to take a look at the file cabinet...

Who is the murderer?  Stay tuned for the conclussion...