by an iraqi photojournalist, ali arkady, expecting to document the heroics of iraqi soldiers, working with the u.s. against isis. >> they are against isis and they are very strong. >> reporter: but arkady says he soon came to learn the soldiers he was embedded with for months, from what's called the emergency response division, were no heroes. and tonight, he is revealing the graphic images, licensed by abc news, that he captured of these important u.s. allies carrying out the torture and murder of civilians, only some of which is suitable for broadcast. was this happening all the time? >> this is happening all the time. >> reporter: this man, he says, was a sheep herder, whose teenage sons were suspected of working for isis. >> there's not even a pretext here of torture in the name of obtaining intelligence. this is just torture for fun. >> reporter: sadistic? >> sadistic. >> reporter: in a remarkable phone call with us, the unit captain, omar nazar, admitted