44-year old Constable Anand Kumar of Rajanakunte police station in Bangalore Rural district fired from his rifle at SI Vijaykumar, injuring him on his head and chest.
The SI, said to be in his 40s, was rushed to hospital but died on the way, Bangalore Rural Superintendent of Police D Prakash, who rushed to the spot, told PTI.
Kumar was immediately taken into custody on charges of murder, he said.
Prakash said the two policemen were involved in a heated argument over allotment of duty by the superior officer when the constable fired at him from his rifle.
Vijaykumar was posted to the police station only three months ago.