The Case Of The Frightened Men - Part 1

Piyush, a writer specializing in murder mysteries, becomes the prime suspect when one of the five friends, Rishab, gets murdered in his presence shot with his own gun in his own house. All of them were getting unsigned letters warning them that now it was their turn. The common thing the five friends was the fact that they had all ragged Piyush during the college days resulting in him falling off from the second floor of the hostel. Is he the one? or is there a twist?