Railway Protection Force constable Chetan Singh has been sent for a mental health checkup following his killing spree on a train where he shot dead his boss and three passengers. While NDTV spoke with his family, who said that everybody was aware of his mental instability and subsequent treatment for it, the Railway Ministry has ruled out any communal angle to the crime, despite the fact that Singh made a marked hate speech caught on camera after killing four people - citing that he 'also killed a Hindu'. Why was a mentally unstable cop armed on duty? And why no probe into a possible communal motive?