. >> as it turns out it's a plain clothed detective from nearby east moline, illinois, as luck wouldit, detective jim weekly is on his way to meet his wife for lunch when he sees the incident unfold. >> i'm slowing up making sure nothing is going wrong. and that's when i see the glistening of the taser wires. >> detective weekly race ls around the front of the cruiser and is shocked by what he sees. >> get the [ bleep ] off him! the first thing i see is every officer's worst nightmare. i see the officer on his back. i see the suspect punching him very fast and violently to the face. >> without hesitation, he joins in the melee. >> my job at that point was to get the suspect to start fighting me, to get him off the officer. >> meanwhile, officer anderson is fighting for his life. >> i was basically only able to see shadows. i decided i was going to have to shoot him before i went unconscious, and that's when i shot mr. mallory. >> i didn't so much hear the first felt shot, i felt it. i felt it going through my chest. >> weekly mistakenly believes that he might have been shot. >> at th