Journalism veterans and media ethicists are demanding answers from CBS News in light of the revelation that the key “witness” in 60 Minutes' recent report on the September 2012 terrorist attacks on the U.S. diplomatic facility in Benghazi, Libya, had previously said he was not at the diplomatic compound on the night of the attack.

“I don't see any way that 60 Minutes would not need to offer an explanation,” said Alex S. Jones, former media writer for The New York Times and current director of the Shorenstein Center on The Press, Politics and Public Policy at Harvard University. "This definitely needs explaining."

The 60 Minutes segment, which aired October 27, includes a lengthy interview with a man identified by the pseudonym “Morgan Jones,” who told the magazine show he was “a security officer who witnessed the attack.”

The piece featured “Jones” and his seemingly heroic efforts “scaling” the compound's 12 foot wall, disabling a terrorist “with the butt end of a rifle” and ultimately seeing the lifeless body of Ambassador Chris Stevens in the hospital.

But The Washington Post revealed Thursday that “Jones,” identified as defense contractor Dylan Davies, told his employer in a written report just days after the attack that he was far from the area at the time. According to the Post, Davies wrote that “he spent most of that night at his Benghazi beach-side villa. Although he attempted to get to the compound, he wrote in the report, 'we could not get anywhere near . . . as roadblocks had been set up.'” He also wrote that he had heard of Stevens' death from a colleague.

That revelation drew concern and complaints from those who monitor media ethics and have worked in newsrooms for decades. Several called for a correction or at least further explanation.

Among them is Kevin Z. Smith, chair of the Ethics Committee of the Society of Professional Journalists and deputy director of the Kiplinger Program in Public Affairs Journalism at Ohio State University, who called for CBS to “internally review its reporting on this story given the latest information that has surfaced. They need to pursue this new information and story angle with the same fairness and intensity that they did in the original reporting.”

In a letter to CBS News' president and chairman, Media Matters founder David Brock called for such a review, modeled on the independent investigation the network conducted after questions were raised about a report on President George W. Bush's Air National Guard service.

Smith said two questions arise from the situation. “First, did Lara Logan and her staff test the accuracy of the information that was given them and exercise care to avoid error?” he asked in an email. “Second, if they are wrong in their reporting, they should show accountability and make needed corrections to their reportage to reflect any mistakes made. That is a key component to establishing and maintaining trust and credibility with the public.”

Numerous media veterans contacted by Media Matters said that The Washington Post report raises questions about whether CBS News properly reviewed Davies' story before the 60 Minutes segment aired.

“What they should have acknowledged was the fact that he wrote a report saying that he wasn't at the site,” said Kelly McBride, ethics instructor at The Poynter Institute and co-author of the new book, the New Ethics of Journalism. “They should have acknowledge that ... they either didn't know about it or they failed to anticipate that critics would use this as a way of tearing down their story.”

She also said other sources could have been used to verify Davies' story: “Considering that this guy, that his very presence at the compound that night is in question, they could have tried to verify from other sources that he was. Other sources, even if those were off the record sources, they could have done something to address this discrepancy.”

Marvin Kalb, former host of Meet the Press, past NBC News chief diplomatic correspondent and one-time Moscow bureau chief, called the situation “a serious problem” for 60 Minutes noting Davies “could not both be there, and not be there, at the same time. It is, to put it mildly, surprising that 60 Minutes did not check this discrepancy before broadcast.”

Marty Steffens, former editor of the San Francisco Examiner and currently a journalism professor at the University of Missouri, called the situation “another reminder that news organizations must be vigilant in confirming information provided by sources. Such as, 'who can corroborate your story?' 'what would others say about your role?'”

Dave Cuillier, Society of Professional Journalists president, agreed: “Accuracy's number one and we've got to get it right and if we don't, which is going to happen inevitably, then we need to correct it. That applies in every situation whether it's an obit in the Green Valley News or 60 Minutes, journalists everywhere should do their best to get it right and apologize and correct when they don't.”

“If the Washington Post version is correct it would appear obvious 60 Minutes failed to do ethical verification of the Sgt. Morgan's claims,” adds Tim McGuire, former editor of The Star-Tribune in Minneapolis and currently a journalism professor at Arizona State University. “The only immutable ethical standard is truth and on the current evidence it does not appear 60 minutes told their viewers the truth.”

For more on conservative media myths about the September 2012 attack, read The Benghazi Hoax, the new e-book by Media Matters' David Brock and Ari Rabin-Havt.