The incident took place near Etmadpur railway bridge when the four cops were accompanying undertrial Pankaj Bhola from Mathura to Firozabad after the hearing and four unidentified persons fled with him, Superintendent of Police Piyush Srivastava said.
The unidentified persons, sitting in the private bus in which Bhola was returning with the policemen, tried to get down from the bus.
When the cops resisted their bid, they shot at constable Jai Narain and threw chilly powder on Ajit Singh, Amarjeet and Subhash Chauhan and feld with Bhola.