but the people who are on the front lines who are actually engaged in trying to defend america against terrorists, they have to rely on the legal advice that they are given. >> reporter: some of the worst abuse occurred at a secret location called cobalt, where detainees were walked around naked or were shackled with their hands above their heads for extended periods of time. cia officers directed detainees hooded down hallways, slapping and punching them. and an admission in cia documents that waterboarding did cause physical harm. abu zubaydah repeatedly waterboarded became completely unresponsive with bubbles rising through his open mouth. internal cia records called a waterboarding 183 times a series of near drownings. torture that wasn't even effective, according to the report. >> it produced little useful intelligence to help us track down the perpetrators of 9/11 or prevent new attacks and atrocities. >> reporter: the cia issued a lengthy and detailed statement saying the...