The Obama administration has promised to back CIA employees who interrogated suspected terrorists within the limits set by Justice Department lawyers under President George W. Bush.  Those limits, we learned last week, permitted techniques such as waterboarding and "walling."

But might some interrogators have crossed the line?

A May 2004 report by the CIA’s inspector general on counterterrorism-related detentions and interrogations might hold answers. But most of the report remains classified, despite efforts by the ACLU to make it public through a freedom of information lawsuit.

Last week’s release of four previously classified Office of Legal Counsel memos regarding interrogations could change that, said Jameel Jaffer, the ACLU’s national security program director, in an interview. Two of the memos repeatedly reference the IG report, and Jaffer said that weakens the government’s case for continuing to withhold the remaining portions of the report.

CIA Inspector General John Helgerson’s report was "tens of thousands of pages long and as thick as two Manhattan phone books," sources told New Yorker writer Jane Mayer for her book, The Dark Side. She writes that Helgerson investigated at least three deaths of CIA-held prisoners in Afghanistan and Iraq and "raised serious questions about the Agency’s mistreatment of dozens more."

The portion of the IG report that was made public – released last May in response to the ACLU lawsuit and available here – measures about a quarter of an inch thick. Most of the released pages are almost completely blacked out, including portions of the title and a full page of the table of contents. Page 15, for instance, reveals only the phrases "Enhanced Interrogation Techniques" and "the waterboard technique."

The report covers the period from September 2001 through October 2003. The Justice Department signed off on certain harsh interrogation tactics no earlier than August 2002, according to what is publicly known. Jaffer said the IG report could provide a window into CIA interrogations before then, when the legality of some methods may have been an open question.

The release of Justice Department memos referencing the IG report in some detail suggests that the administration "has clearly concluded already that more information from the report can be disclosed," Jaffer said. Liberal blogger Marcy Wheeler, also known as emptywheel, lists the references in detail.

Asked if more of the IG report will be made public and whether its contents could reveal the extent to which interrogators followed legal parameters, DOJ spokesperson Tracey Schmaler said, "We can’t comment."