Four little-known online commentators – known as Web-loggers, or bloggers for short- were instrumental in landing a blow to CBS News with their reports that documents involving President Bush’s Air National Guard service may have been faked.

The four – John Hinderaker, William Ardolino, Charles Johnson and the pseudonymous “Allah” – led an interconnected real-time investigation into the authenticity of four documents that CBS, in its “60 Minutes II” broadcast last Wednesday, said proved that Mr. Bush applied pressure to get out of his Air National Guard service in August 1973.

Starting Thursday morning, the four bloggers – simultaneously doing original reporting and investigative work – created enough skepticism over CBS’s reporting that the network was forced to dedicate the opening segment of last Friday’s “CBS Evening News with Dan Rather” to defending itself.

The allegation leveled by the four bloggers is that the documents CBS used are sloppy and politically motivated forgeries. They base their claims on assertions that the documents contain spacing and typographical constructions that were impossible to make using electric typewriters available in 1973.

CBS News, which did not return a telephone call from the Sun, has said it stands by its report. During last Friday’s “CBS Evening News with Dan Rather” broadcast, Mr. Rather defended CBS News’ use of the documents, asserting “Definitive proof has not come out to refute them.”

The New York Sun interviewed three of the four bloggers – Charles Johnson did not return repeated e-mailed requests seeking comment – and was able to create a timeline of how these four nonjournalists created an ongoing dilemma for one of the largest and most established journalistic organizations in America.

At 7:51 a.m. last Thursday, Mr. Hinderaker, a Minneapolis-based trial lawyer and co-author of the politically conservative “Powerline” blog, noted that several of his readers had e-mailed him with questions over the typographical appearance and tone of the alleged documents.

He told the Sun that most of his early correspondents referenced a post from the previous night on the FreeRepublic Web site dated at 11:59 p.m. by a poster named “Buckhead” that disputed the memo’s veracity based on typographical issues; repeated attempts to reach “Buckhead” via e-mail were unsuccessful.

Mr. Hinderaker described the outpouring of reader commentary and interest on the issue as “incredible. We had ex- and current-military types writing in, saying the language in the memo was wrong. We had computer and typewriter hobbyists writing in saying that there was no way 1973-era typewriters were capable of those fonts.”

Mr. Hinderaker said the comments came in to their blog “so fast that we could only post samples of what we got. And anything we posted got linked by other blogs and generated hundreds more e-mails from people familiar with military memos and typewriters.” He said that there was virtual unanimity from these e-mailers that the documents were, as he put it, “utter B.S.”

At approximately 8:30 a.m., Washington D.C.-based marketing manager Mr. Ardolino logged on to his computer at his job. Mr. Ardolino, who runs the politically conservative INDC Journal blog, said he noticed the Powerline blog entry and was interested in it, so he followed the link provided to CBS News’s Web site and downloaded the documents.

“Reading [the documents] made clear to me that something was wrong,” he said. “Their tone read more like an e-mail than a formal analysis filed by career military men. I didn’t believe that anyone would title a memo “CYA,” even if they were trying to [protect themselves.]”

Shortly after 9:30 a.m., Mr. Ardolino took matters into his own hands and sought an expert opinion on document forgery. As he described it, “I simply [searched out] a forensic document members organization and somehow wound up speaking to Dr. [Phillip] Bouffard.”

Dr. Bouffard designed the database program of old fonts that is widely used by academic and law enforcement organizations worldwide to determine the authenticity of documents. Dr. Bouffard, while acknowledging that a conclusive opinion is difficult to generate given the absence of the original document, told Mr. Ardolino he was “more than 90% certain they were fakes.”

The linking generated by Mr. Ardolino’s posting of the interview at 2:41 p.m. drew more than 25,000 hits to his eight-month-old site.

For its part, CBS News said it had consulted with “numerous” handwriting experts who validated its work. The only expert it acknowledged consulting, Marcel Matley, a San Francisco based librarian, has a background in handwriting and signature analysis.

At 10:36 a.m., “Allah,” the proprietor of a heavily trafficked news analysis site calledAllahpundit.com, posted his first links to the developing controversy.

“Allah,” who declined to give his real name or occupation, told the Sun via email that he came across the controversy on Powerline “and found it interesting. Much more so than the usual ‘tinfoil hat’ stuff that’s typically involved in conspiracy theories.”

“Allah’s” site acted as a clearinghouse of sorts for Web log readers, offering detailed commentary on the various posts and links going up around the Internet on the document controversy.

Seizing on the typeface and font inconsistencies, Allah’s site linked to a half-dozen other sites where bloggers were investigating the authenticity of the documents, all of which precisely replicated the allegedly typewriter produced documents.

Later that evening, “Allah” got a lengthy e-mail from an Air National Guard officer which took exception with CBS’s documents from the standpoint of what he alleged were “egregious formatting and terminology errors” with respect to military bureaucratic protocols of the 1970s.

“Allah” did not provide the Air National Guard officer’s name, but wrote on his blog that the officer’s name and rank appeared on several documents he discovered in an online search.

The most detailed analytic work done on the documents was by Charles Johnson, a Web-site designer whose “Little Green Footballs” Web site, with nearly 25,000 visitors a day, is a highly read blog focusing on national security issues. Mr. Johnson, according to Messrs. Hinderaker and Ardolino, did the most exhaustive typeface and font testing of CBS’s documents.

At 11:30 a.m. last Thursday, Mr. Johnson posted the first of what would be almost a dozen tests over the next few days on the CBS documents, all of which showed remarkable similarities between the allegedly typewritten documents and documents produced by Microsoft Word.

To demonstrate the similarity, he overlaid his MS Word version against numerous CBS document that he downloaded from CBS News’s Web site. Each document lined up perfectly.

“When you saw a guy like Charles Johnson, who has been deeply involved with computer publishing since the 1970s, provide a detailed series of tests indicating that there was no way these documents were created on anything other than Microsoft Word, you became comfortable in asserting to everyone these were fakes,” Mr. Hinderaker said.