Watch a Heroic Police Officer Take Down This Dangerous Mass Shooter in Less Than 15 Seconds (VIDEO)

Tucson mass shooter David French is captured on camera opening fire. Credit: Screenshot from Empire Pizza & Pub camera footage

Footage has emerged showing the moment that a heroic Tucson police officer took down a dangerous mass shooter last week, who should never have been free to start with.

As FOX 10 Phoenix reported, a mass shooting happened around 2 a.m. Sunday, July 19, on Congress Street and Sixth Avenue, right outside Empire Pizza.

Tucson Police revealed that there was a confrontation between two groups who knew each...