"There's definitely a cover-up," the witness, Sgt. Samuel Provance, said. "People are either telling themselves or being told to be quiet." Provance, 30, was part of the 302nd Military Intelligence Battalion stationed at Abu Ghraib last September. He spoke to ABCNEWS despite orders from his commanders not to. "What I was surprised at was the silence," said Provance. "The collective silence by so many people that had to be involved, that had to have seen something or heard something."