In a blockbuster story Hagan revealed that a mere five days after setting up an independent panel to investigate Rathergate, CBS quietly hired Erik T. Rigler, a former FBI agent, Navy aviator and now a private detective, ostensibly to track down the source of the forged documents Rather used on his "60 Minutes" show to attack President Bush's Texas Air National Guard service.

CBS never mentioned Rigler's investigation in the list of interviews and other matters in the independent panel's final report on Jan. 10, although the network had promised transparency in investigating the memo scandal.

Moreover, of a half-dozen CBS News producers who spoke to the Observer, only one had even heard a rumor that the network had hired the private investigator, Hagan wrote. But, he added, Rather and his producer Mary Mapes were both aware of Rigler's assignment and as a result were no longer conducting an independent probe of the source of the forged documents.

Armed with all Mapes' leads and notes about the National Guard story she gave him, Rigler's investigation led him to the man who had given them to CBS, former National Guard employee Bill Burkett. It also ended there.

And this is where the matter becomes bizarre. Instead of uncovering the source of the documents, Rigler wrote a two-page memorandum about Mary Mapes that he handed over to the panel, led by former Attorney General Dick Thornburgh and former Associated Press head Louis Boccardi Jr.

Hagan reported that the memo contained personal information about Mary Mapes, including her answers to a line of inquiry about her estranged father. Rigler made no report on his failure to find the source of the forged documents.

Mapes' lawyer, Richard Hibey, told Hagan that Mapes was dismayed to learn that the ostensible investigation of the documents had turned into an inquiry into Mapes herself.

"When she saw the report she felt completely betrayed by [60 Minutes Wednesday producer Josh] Heyward and CBS," Hibey said. "Because this guy didn't apparently do what Heyward said he was going to be doing."

Rigler declined to comment on his work for CBS, and a spokeswoman for CBS News told Hagan that "CBS News hired a private investigator with the full knowledge and enthusiastic approval of all of those involved in the original Sept. 8 report for one purpose only: to help get to the bottom of the authenticity and origin of the documents."

The CBS spokeswoman said the private investigator's aims were not to find critical information about any of CBS's producers. "The investigator's brief report was not critical of any individuals involved in producing the original Sept. 8 report," she said. "To this day, the basic questions about the documents have not been answered, but we remain hopeful that, one day, they will be."

It now appears that Rigler was actually hired to do what he did â€" probe the activities of Mary Mapes instead of digging for the source of the forged documents.

Hagan concluded: "But whatever breaches of journalistic procedure Ms. Mapes may have committed, CBS News still hasn't solved the mystery surrounding her fundamental news judgment: Was she the victim of a hoax or not?"

Given all this, it's no wonder CBS wants to put the clamps on whatever Dan Rather might have to say on the subject.

Editor's note: