Senior Superintendent Procopio Lipana, chief of the Central Police District-Criminal Investigation Unit (CPD-CIU), identified the bystander as Joy Raymundo.
She was waiting for a ride near Mindanao Avenue when the shootout took place. She suffered a gunshot wound in the thigh and was taken to the hospital for treatment.
The other person injured in the incident is believed to be one of the three suspects who figured in the shootout with cops.
Lipana said the incident happened around 9:45 a.m.
TMG Mobile Car 22 with license plate SEC-593 was cruising on Mindanao Avenue when they spotted a maroon Toyota Corolla with license plate UAA-969. TMG members SPO2 Fructuoso Catubig, PO2 Marcelino Dacoyco and PO1 Ruben Mission followed the car because they found the license plates suspicious-looking.
The car then stopped and three men alighted, opened fire at the TMG mobile patrol car, shattering its windshield and busting a tire. Raymundo was hit by a stray bullet.
The traffic policemen managed to retaliate and hit one of the suspects, who went back to their car and sped off. But the cops could no longer give chase because of the flat tire.
Efforts to track down the vehicle of the suspects by police back-up failed.
Lipana said police recovered at least 10 slugs from a M-14 and M-16 firearms at the crime scene.