Complex sentence: The video showed an American helicopter firing on a group of men in Baghdad, one of them a journalist, and two others Reuters employees carrying cameras that the pilots mistook for anti-tank grenade launchers (RPG-7).
Split into simpler sentences: The video showed an American helicopter firing on a group of men in Baghdad. One of the men was a journalist, and two other men were Reuters employees carrying cameras that the pilots mistook for an anti-tank grenade launcher (RPG-7).