La David Johnson died after returning to kill zone to save comrades

Sgt. Johnson was in an armed pick-up truck that was in front of the vehicle carrying the other three men when the attack began

He and others in the truck initially got out to return fire but got back into the vehicles when they realised they were dangerously outnumbered

They sped ahead 200 yards then realized the other men, who were in an unarmed Land Cruiser, were behind and in the kill zone

Two other US soldiers got out of the truck on foot and marched back towards the Cruiser while Johnson covered them from a mounted machine gun on the pick-up truck