Orlando Mass Shooting: Mateen Was About to Kill More ... Chief Describes Final Assault

Mass murderer Omar Mateen was in a fierce gun battle with cops in and outside Pulse Nightclub before he retreated into a bathroom ... where Orlando's Police Chief ultimately made the call to take him out.

Chief John Mina described Mateen's arrival to the club and the firefight that immediately erupted. He also explained why he made the call to use explosives and an armored vehicle to go in and get Mateen when he was holding hostages.