The accused were identified as Chinder Pal, 22, and Irshad Khan, 19. They were arrested on Saturday night from their native place in Alwar on a tip-off, said Deputy Commissioner of Police Chinmoy Biswal.
The incident came to light in the early hours of September 12 when a passerby spotted the body of victim, Ram Avtaar Meena, in Meethapur area. Meena was posted at Ambedkar Nagar Police Station as head constable and lived in the Meethapur area.
During interrogation, Chinder Pal and Irshad Khan told the police that they were in south Delhi for stealing bikes in Jaitpur area. They had on September 11 managed to get a countrymade pistol for the crime, police said.
"They were joined by another accomplice who is yet to be arrested. On the day of the crime, they all came on a bike in Meethapur area and planned to steal a bike parked in a residential area of Tanki Road. While they were trying to unlock the bike, Meena who was returning to his residence after seeing off a relative, spotted them," he added.
"He suspected their movement. In a scuffle, Chinder Pal fired at Meena. They later escaped from the spot after leaving Meena in a pool of blood," the officer said.
"Effort is on to nab their third accomplice," he added.
( With inputs from IANS )