Assistant Sub-Inspector Muhammad Raiz was on a routine patrol in Sector G-9 when he saw some men acting in a suspicious manner near a car outside a hotel.
Riaz rushed towards the men, who opened fire and killed him instantly, a police spokesman said.
Riaz's bodyguard and three passersby who tried to help the police were injured in the firing. They were taken to the Pakistan Institute of Medical Sciences.
One of the car thieves was overpowered by local residents while his companions managed to escape, the police spokesman said.
