Watch Muzzle for Free: How to Stream the Movie Online at 123Movies. . LAPD K-9 officer Jake Rosser has just witnessed the shocking murder of his dedicated partner by a mysterious assailant. As he investigates the shooter’s identity, he uncovers a vast conspiracy that has a choke-hold on the city in this thrilling journey through the tangled streets of Los Angeles and the corrupt bureaucracy of the LAPD.