As time goes by, we learn more about the U.S. military's abusive interrogation of terror suspects overseas since the Sept. 11, 2001, attacks on America. We know about waterboarding, intimidating detainees with snarling dogs, humiliating prisoners by parading them nude before women soldiers and shackling them to the floor for hours in extreme hot or cold.

FBI agents assisted in some of these cases, although they often clashed with their military counterparts over aggressive intelligence-gathering methods because they questioned whether they were legal or effective, according to a Justice Department audit released this week.

The 437-page report portrays the FBI as taking a principled stand against abusive interrogations and torture. But the audit did take issue with FBI superiors who did not instruct agents how to respond to military interrogators who used tactics not permitted by the agency.

Some FBI agents went so far to open a "war crimes file" to document accusations against American military personnel conducting abusive interrogations. They were eventually ordered to close the file, suggesting that Bush administration officials were more interested whether the tactics yielded valuable intelligence. Violations of law, apparently, were a secondary concern.

The Justice Department audit is disturbing in many respects. It provides the most detailed account to date of tactics employed against suspected terrorists by the U.S. government. The document describes a "frequent flier program," in which multiple tactics were deployed, such as sleep depravation, the use of strobe lights in conjunction with loud rock music, the twisting of thumbs backward and sexual taunting, among others.

The report also sheds light on the efforts of FBI agents who refused to participate in the most aggressive intelligence-gathering methods and how they were essentially rebuffed when they raised concerns about the legality of the tactics and how those techniques could pose problems when the Pentagon attempted to try terror suspects in military tribunals.

After the Sept. 11 attacks, it is understandable that the Bush administration would want to use every tool at its disposal to ensure there would not be another such siege. Yet the United States has long been considered a standard bearer in terms of human rights, due process and justice. Credit the front-line FBI agents who raised concern about the harsh interrogation techniques used in Iraq, Afghanistan and Guantanamo Bay.

This review raises more questions. Congress should demand an independent review of these matters to determine whether higher-ups in the FBI willfully ignored the concerns of field agents. Moreover, Congress needs to know for a certainty whether military interrogators have changed their interrogation techniques to better conform with U.S. standards of justice.