Kumar Saurabh was undergoing training at Bhagalpur police line and currently deputed in Sultanganj for 'Shravan Mela', Superintendent of Police Ashish Bharti said.
He was called at the railway station by someone last night, where an unidentified person shot him in the head around 9 PM, the SP said.
The constable was admitted to Munger Sadar hospital where the doctors referred him to Patna. He died around 2 AM while being taken to Patna. Railway police are investigating the matter, he said.