Joe Darby knew what he saw was wrong, but it took him three weeks to decide to hand those photographs in. When he finally did, he was promised anonymity and hoped he would hear no more about it. But he was scared of the repercussions from the accused soldiers in the photos.
"I was afraid for retribution not only from them, but from other soldiers," he says.
"At night when I would sleep, they were less than 100 yards from me, and I didn't even have a door on the room I slept in.
"I had a raincoat hanging up for a door. Like I said to my room mate, they could reach their hand in the door - because I slept right by the door - and cut my throat without making a noise, or anybody knowing what was going on, and I was scared of that."
When the accused soldiers were finally removed from the base, he thought his troubles were over.
And then he was sitting in a crowded Iraqi canteen with hundreds of soldiers and Donald Rumsfeld came on the television to thank Joe Darby by name for handing in the photographs.
"I don't think it was an accident because those things are pretty much scripted," Mr Darby says.
"But I did receive a letter from him which said he had no malicious intent, he was only doing it to praise me and he had no idea about my anonymity.
"I really find it hard to believe that the secretary of defence of the United States has no idea about the star witness for a criminal case being anonymous
