Four CBS News employees, including three executives, have been let go for the parts they played in preparing the controversial "60 Minutes Wednesday" election-season story about President Bush's National Guard service, CBS announced Monday.

Asked to resign were 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, according to CBS.

The producer of the piece, Mary Mapes (search), was terminated, the network said.

Longtime CBS News anchor Dan Rather (search), who was the correspondent on the September segment, announced his departure as anchor of "CBS Evening News" late last year. His final show will be March 9.

The CBS oustings came with the release of the final report by an independent panel assigned to look into what happened with the CBS Bush National Guard story (search), which alleged that the president had shirked some of his guard duties and received special treatment during his Vietnam War-era service.

The Sept. 8 CBS report turned out to be based largely on memos whose authenticity could not be proven.

To read the CBS report, click here (pdf).

Top CBS executive Leslie Moonves had appointed former Republican Attorney General Dick Thornburgh (search) and Louis Boccardi (search), retired president and chief executive officer of The Associated Press, to investigate what went wrong, and they delivered their report last week.

The panel stopped short of saying the CBS story arose out of any political bias on the part of the network or its news coverage.

Instead, the report concluded that the problematic National Guard segment was aired because of "myopic zeal" on the part of CBS to break the story first.

The panel said Mapes had misled her superiors about the documents and the background of her source, retired Texas National Guard Lt. Col. Bill Burkett.

CBS News executives relied too heavily on Mapes, who only months earlier had broken the story about the Abu Ghraib prison scandal and had been investigating Bush's National Guard service since 1999. Howard, who had begun supervising "60 Minutes Wednesday" in June, gave too much deference to her and Rather, the panel said.

Reached at her Dallas home Monday, Mapes said: "I haven't seen the report yet, so I won't be saying anything until I do."

Criticism has swirled about how Rather was handled in the so-called "Memogate" scandal.

Rather, who narrated the National Guard report, was only faulted for "errors of credulity and overenthusiasm" in the panel report.

Rather announced his March resignation on "CBS Evening News" on Nov. 23, saying he was planning to retire soon anyway. He said he was not stepping down over the National Guard story controversy.

"The mistake of Dan Rather is that he said, 'I don't make mistakes,'" Jeff Jarvis, who runs the Weblog site Buzzmachine.com, told FOX News on Monday. "There was a lot of buck-passing here."

CBS thought it had an important scoop with the National Guard story, but critics immediately questioned it, saying at least one memo purportedly written by Bush's squadron leader in 1973 appeared to have been written on a modern computer using Microsoft Word.

Rather and CBS initially defended the piece. Rather later apologized on Sept. 20, before CBS appointed the investigative panel.

"We made a mistake in judgment," Rather said, "and for that I am sorry."

The "60 Minutes Wednesday" segment alleged that Bush refused a direct order to take a required medical examination, and also alleged that Bush asked his commanding officer, Lt. Col. Jerry Killian (search), if he could skip drills in order to work on a political campaign.

The memos used by the network bore the signature of Killian, commander of Bush's Texas Air National Guard (search) fighter squadron. Bush served in the Guard from 1968 to 1973.

Killian died in 1984. His wife and son took issue with the memos, saying Killian did not keep records like the ones CBS said it had gotten copies of.

The "60 Minutes" report also cited a memo from Col. Walter "Buck" Staudt, former commander of the Texas Air National Guard, that allegedly pressured another officer to "sugarcoat" Bush's record.

Staudt appears to have retired before that memo was purportedly written.

Retired Major Gen. Bobby Hodges (search), who backed up the validity of the memos on the CBS broadcast, later recanted his statements, saying that he stopped believing the memos were real once he got a look at them.

After the CBS segment aired, Bush's National Guard service became a hot campaign issue during the contentious presidential race for the White House between Bush and Massachusetts Sen. John Kerry.

The Bush camp defended the president's service and released its own documents in an effort to prove that the allegations and questions about whether he fulfilled his duties were unfounded.

Questions remain whether there was any truth to the allegations about Bush's military service, despite the unreliability of the CBS memos. Independent reports backing up the CBS segment's assertions have not been proven.

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.

"The committee did not find conclusive evidence that the documents were forged," Paul Burkam, executive editor of Texas Monthly magazine, told FOX News. "Something can be true and yet can be forged. What we always look at is, Is it accurate?"

The CBS probe team concluded in its report that the network news organization failed to follow basic journalistic principles in preparing, reporting and following the Bush piece.

CBS News then made matters worse with its "rigid and blind" defense of the "60 Minutes Wednesday" segment, the panel reported.

It found that the news organization should have set the record straight earlier.

"The panel finds that once serious questions were raised, the defense of the segment became more rigid and emphatic, and that virtually no attempt was made to determine whether the questions raised had merit," the report concluded.

CBS News President Andrew Heyward (search) on Sept. 10 ordered West, one of the ousted executives, to review the opinions of document experts who had seen the disputed memos and unnamed sources which formed the basis for the Bush National Guard story.

That review never took place, the panel's report said.

"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 report said.

Heyward ultimately kept his job. The panel said the CBS News president had explicitly urged caution before the report aired.

The panel made a number of recommendations for changes, according to CBS, including:

— Appoint a "senior standards and practices" executive who would report directly to the president of CBS News and would review all investigative reporting, use of confidential sources and authentication of documents. Other staffers could go to the new executive confidentially with any concerns they might have about a story.

— Foster an atmosphere in which competitive pressure was not allowed to prompt airing of reports before all investigation and vetting is done.

— Allow senior management to know the names of confidential sources as well as all relevant background about the person needed to make news judgments.

The Associated Press contributed to this report.