That can certainly happen, but we have no evidence that this was the case here. There are rapists and murderers in all levels of society including the military.

The high level of discipline in the military helps to prevent the normal people from degenerating into criminals. Rapists and murderers however, can simply take advantage of the opportunities presented by battle conditions to commit their crimes.

The situation we saw at the abu ghraib prison was a clear example of the lack of discipline allowing relatively normal individuals to degenerate into criminals. I don’t think that this story fits that template.