I wouldn't name the film (classic) or else the climax will be disclosed.

It's a well acclaimed film, depicting real life events. Court case is settled with this explanation:

A & B are fighting. C is near by.

3 of 6 bullets are shot from A's revolver. All miss and are accounted for.

C shoots 1 bullet and assumes it's this bullet that killed B.

B shoots one bullet from his own revolver and kills himself accidently.

C picks up B's revolver (murder weapon) and hides it, to frame A (only A's revolver is remaing at the scene) . C had picked up the revolver with a handkerchief and hence B's figerprints stay in tact.

The Blooper is, why did C use extra caution to preserve B's fingerprints if the idea was to hide/ destroy that part of the evidence ??