FF Chased Down Terror Suspect Before NYPD Arrived

Marine veteran and volunteer firefighter William Harris was driving a truck down West Streeet on Tuesday when he heard a collision and spotted terror suspect Sayfullo Saipov step out into the intersection with two real-looking guns in hand. Harris got out of the truck and video captured him chasing down Saipov before NYPD officers arrived.

"This is New York. You don't mess with us," Harris told WPIX. "I didn't think twice. I went after him and I had to stop him."