A shooter with an AR-15 opens fire on 300 clubbers in Orlando, Fla.; hiding in the bathroom, he takes multiple hostages; it's a race against time to save their lives; in Washington, a thief steals a shotgun from a Walmart, and K9 officers track him.

In Wisconsin, a suspected hit-and-run takes a dangerous turn when a witness opens fire leaving two officers down. In Georgia, a mother and her children hide in a closet after a gang leader barricades himself in their apartment.