A hitman with a sniping gun is settled on the rooftop of a skyscraper.    He has his target in sight.    The safety is switched off.  Timing is good, no  moon, no wind, a group of bikers ride their loud motorcycles covering the noise.  The index presses the trigger, the bullet sings its deadly song through the air, breaks the window and enters its final destination; the businessman’s head.  The hitman reloads the rifle in an automatic reflex, in case another bullet is required.  It’s not the case.  He examines to make sure his part of the deal is completed; his target is down.   He takes a look at the neighbor’s appartments windows to see if he’s been noticed. He sees a woman being molested, probably her husband.  She is heavily bleeding, her husband had just picked up a large knife.  He is clearly out of control.

Either –
The hitman takes the shot, kills the husband. He then has to pack up and leave.  The woman will call the police.

He waits, look and sees the whole scene.  The man then pleads not guilty on self defence wins and is released.  The Hitman decides to take justice in his own hands.