Six persons on two motorcycles reached the police station last night and challenged Station Officer (SO) Pramedra Singh, said Additional Superintendent of Police Dinesh Kumar Singh.
When he did not come out, the assailants shot dead Mahadaev Prasad Misgra, the ASP said, adding they were accused of stealing a mobile.
On the basis of the SO's complaint, a case has been registered against six persons and investigation is on, he said.
Meanwhile, terming the incident as the "peak of anarchy" in the state, UP BJP spokesperson Vijay Bahadur Patahak claimed that 1,040 policemen have been killed during the SP rule.