I would like to tell u all that since i am a Psychology student I am doing an analysis on why Raj shot Navin.
Raj has not given Navin mukhti but i believe that Navin was toooo tired to give explanations to everyone abt his innocence.
I am sure YOU would say that if I would have been at Navins place I wouldnt have done that.
But it is not so easy u see.
There was no one for Navin to MOTIVATE HIM close-by.
As per Raj's charecter analysis i would say that He is a strong headed person who has lots of patience & he waits for the right time to bang the hammer if he finds anything fishy.