Because of such documented discrepancies, Justice Department officials and legal experts regard the wateboarding abuses as cases that hold the most promise for prosecution.
Even so, the cases are hampered by legal and logistical complications.
The U.S. anti-torture statute requires proving that an individual "specifically intended to inflict severe physical or mental pain or suffering," a daunting legal threshold.
Beyond that, officials said it's not clear that any CIA interrogators were ever informed of the limits laid out in the Justice Department memo.
"A number of people could say honestly, correctly, 'I didn't know what was in it,' " said a former senior U.S. intelligence official familiar with the inner workings of the interrogation program.
The CIA report also cites cases in which interrogators engaged in potentially illegal improvisations. One interrogator brandished a gun, former CIA officials said. Other prisoners reportedly were threatened with bodily harm, including being buried alive.
Agency spokesman Paul Gimigliano said the CIA cooperated extensively in "referring actions for potential prosecution, and in dealing with career prosecutors who decided if and when specific cases would be pursued in court." To date, only one case has been. In 2007, a CIA paramilitary contractor, David A. Passaro, was sentenced to eight years in prison after being convicted of using a flashlight to beat an Afghan detainee who later died.
In addition to the sweeping 2004 document, former CIA Inspector General John L. Helgerson, who recently retired, also produced a dozen or more follow-on reports that could motivate the Justice Department probe.
Among them are examinations of other cases that involved the deaths of prisoners in agency custody.
In 2002, an Afghan prisoner died of hypothermia after being stripped, doused with water and left overnight in a frigid CIA lock-up near Kabul, the Afghani capital. One CIA officer faced internal sanctions over the episode, but the undercover operative in charge of the facility later was promoted to be chief of station in Baghdad, former CIA officials said.
A year later, an Iraqi prisoner died of asphyxiation after being captured in a violent raid by Navy SEALs and then having his arms chained behind his back in a CIA interrogation cell at the notorious Abu Ghraib prison.
The leader of the SEAL team was later acquitted of criminal charges. The CIA interrogator, Mark Swanner, has not faced prosecution.
The two cases are believed to have been among 19 examined by a special Justice Department task force set up in Alexandria, Va., in 2004 to investigate CIA abuses. The panel did not investigate the use of wateboarding.
Former Justice Department officials familiar with the effort said that 17 of the cases were rejected by mid-2006. It is not clear what became of the other two. Officials cited a host of problems, including difficulty locating witnesses and identifying documents - such as clinical examinations or autopsies - that could withstand scrutiny in federal court.
"We wanted to make these cases," said a former Justice Department official familiar with the matter. "We looked at them as hard as we could and they just weren't there. They weren't there because of the way they were investigated, because of the facts, because of the lack of witnesses and evidence."
