New York- Four CBS executives were fired Monday following the release of an independent investigation that said a “myopic zeal” led to a “60 Minutes Wednesday” story about President Bush’s military service that relied on allegedly forged documents. The 224-page report by former Attorney General Dick Thornburgh and former Associated Press President Louis Boccardi did not directly fault the correspondent on the Sept. 8 story, Dan Rather, who is stepping down as anchor of “CBS Evening News” in March.

While the investigation found the network failed to follow basic journalistic principles in preparing the “60 Minutes Wednesday” piece, it said it found no evidence that a political agenda by network officials contributed to the decision to air it.

The investigators found “myopic zeal” to break the story and faulted the highly respected producer of the segment, Mary Mapes, in explaining why CBS News had produced a story that was neither fair nor accurate and did not meet the organization’s internal standards. “The combination of a new 60 Minutes Wednesday management team, great deference given to a highly respected producer and the network’s news anchor, competitive pressures, and a zealous belief in the truth of the segment seem to have led many to disregard some fundamental journalistic principles,” it said.

The report places most of the blame on a producer of a story on President Bush’s National Guard service for presenting “half truths as facts,” NBC’s Lisa Myers reports.

The story, which aired on Sept. 8, relied on four documents allegedly written by one of Bush’s Texas Air National Guard commanders in the early 1970s to raise questions about whether he had fulfilled his obligations. Questions about the authenticity of the documents were raised almost immediately, with some experts saying that it appeared they were written on a computer not invented at the time.

Although the panel said it couldn’t prove conclusively the documents were forged, it said CBS News failed to authenticate them and falsely claimed an expert had done so when all he had done was authenticate one signature.

A statement from CBS Chief Executive Officer Leslie Moonves detailing the network’s response to the investigation said that network executives had asked for the resignations of Senior Vice President Betsy West, who supervised CBS News primetime programs; “60 Minutes Wednesday” Executive Producer Josh Howard; and Howard’s deputy, Senior Broadcast Producer Mary Murphy. Mapes, the producer of the piece, was terminated, it said.

In assessing Rather’s role in the debacle, the report said the veteran anchorman ” does not appear to have participated in any of the vetting sessions or to have even seen the segment before it was aired.” It noted that he was busy overseeing coverage of the GOP convention and Hurricane Frances in Florida at the time.

Moonves said in his statement that Rather “asked the right questions initially, but then made the same errors of credulity and over-enthusiasm that beset many of his colleagues in regard to this segment.”

Given Rather’s apology and announcement that he was stepping down, Moonves said further action against Rather was not warranted.

The report also said CBS News had compounded the failure to properly vet the report with a “rigid and blind” defense. Rather and the network stood behind the story for 12 days before conceding that the authenticity of the documents could not be confirmed and ordering the independent investigation.

It also noted that Heyward ordered West two days after the report aired to review the opinions of document examiners and confidential sources who had supported the story, but said no such investigation was done.

“Had this directive been followed promptly, the panel does not believe that `60 Minutes Wednesday’ would have publicly defended the segment for another 10 days,” the panelists said.

The documents at the center of the report were purported to be from the late Lt. Col. Jerry Killian, one of Bush’s commanders in the Texas Air National Guard. Among them were a purported order from Killian for to report for his annual physical exam and a discussion of how Bush could get out of “coming to drill.” Killian also reportedly felt pressured to sugarcoat an evaluation of then 1st Lt. Bush.

Moonves said the investigators spoke with more than 66 people, including 32 from CBS News, handwriting experts, former Texas Air National Guardsmen and others in preparing their report.