A CNN investigation by Special Investigations Unit Correspondent Abbie Boudreau, "Killings At The Canal: The Army Tapes," reveals why the Army's rules for holding detainees may have led to the murders of four Iraqis by three decorated Army sergeants at a Baghdad canal. CNN obtained 23½ hours of extraordinary Army interrogation tapes that detail the crime and include a confession by one of the sergeants. READ MORE

A group of 13 soldiers left Iraq holding on to a secret -- the murders of four detainees at a Baghdad canal. They were told not to say a word, and for nine months, they kept quiet. Then, one of the 13 soldiers reported the crime and the secret was out. FULL STORY

After numerous requests, one day in September, a two-page single-spaced typed letter arrived in the mail at CNN from former 1st Sgt. John Hatley. "There are some issues I would like to take this opportunity to address," he wrote. FULL STORY