The faked beheading story broadcast on two Arab language television stations and sent out on international news services early Saturday was based on a grainy video that was made by three Bay Area residents as an experiment to find out how quickly erroneous information could be spread by the Internet.

The experiment had a delayed reaction, but when it came, it did so more dramatically than the people who made the video ever dreamed.

For almost an hour Saturday morning, the Associated Press reported that a 22-year-old San Francisco man, Benjamin Vanderford, had been beheaded in Iraq. The report of Vanderford's death was based on a 55-second video clip that Vanderford and two friends had faked and distributed via the Internet. The story also was picked up by the Reuters news service, and the grainy video was broadcast by two Middle Eastern television stations.

In an interview with The Chronicle hours later, two of the three filmmakers responsible for the clip said they had never expected it to be disseminated so widely, and they blamed the mass media for publicizing the stunt without making sure that the video was genuine.

"We never intended this to be taken as real," said Robert Martin, a 23- year-old Pleasanton man who produced the video with his girlfriend, Laurie Kirchner, 20, and with Vanderford.

The video, which is intercut with grisly photographs of war victims taken from a Middle Eastern Web site and features a recording of someone reading the Quran on its soundtrack, was originally made in May and posted to two file- sharing sites, Soulseek and Kazaa. It all but disappeared until its appearance this weekend on www.islamic-minbar.com, a Web site in Arabic that has posted communiqués from Islamic radical groups and videos of victims who were beheaded by militants.

Soon after it appeared on the Islamic-Minbar site, the video was picked up by the Associated Press in Cairo, Reuters News Service and two Middle Eastern television broadcasters. From there, it quickly spread through the media by being picked up by newspapers, radio stations and television news operations.

Even though the video portrays only somebody making a sawing motion against Vanderford's neck with a knife, the Associated Press repeatedly characterized the depiction in the clip as a "beheading" -- and its first four stories about the video stated flatly that Vanderford had been "beheaded."

Associated Press Deputy Managing Editor Tom Kent said the news service had reported the beheading as factual because the video had been broadcast on a Web outlet that has previously published information about terrorist group activities in the Middle East that turned out to be true.

In an interview with The Chronicle, Kent said the site has provided valuable news leads and the Associated Press is careful to review the site's information before distributing it.

"We spend a lot of time throwing out things that we don't trust," he said. "But if somebody is going to go to the kind of effort they did in this case, some things are going to get through."

Generally, stories based on postings from the Web site are qualified with a phrase such as "the information could not be independently verified."

But in the case of the video, none of the first four stories the Associated Press transmitted to its members carried that caveat, and the story that finally did state that the authenticity of the video could not be determined was published almost 90 minutes after the first version went out.

Kent could not explain why the disclaimer had not been added earlier but suggested that the story had been published before it could be thoroughly authenticated "because in this case, everything was just happening fast and furious."

"Verifying a beheading in Iraq is not something that you are going to do in an hour," he said.

Kent said the episode showed the vulnerability of the news media to manipulation in reporting on the shadowy activities of terrorist organizations and militant groups.

"It certainly emphasizes the importance of being as careful as we can in our reporting and writing," he said. "It's a very delicate line that we and other media have had to walk in reporting on terrorism."

In part, the video appears to have been taken seriously because Islamic militants have recently beheaded three hostages -- U.S. businessman Nicholas Berg, South Korean translator Kim Sun Il and Bulgarian truck driver Georgi Lazov -- as part of their effort to force the U.S. and its allies out of Iraq. Another American, journalist Daniel Pearl, was killed the same way in Pakistan in 2002.

Nevertheless, Ben Bagdikian, author and former journalism dean at UC Berkeley, said Saturday that the Associated Press should have stated that the information taken from the militant Islamic Web site was not independently corroborated.

"Every reporter's safety valve is to put it in the conditional, to use the words 'alleged' or 'reported,' " Bagdikian said.

"Having said that, I think if we were in normal times and someone heard of a beheading without very specific details and reasons, it would not be picked up by a responsible news service," he said. "But given the fact that there is a war in Iraq and there have been beheadings of foreign nationals in Iraq, it makes it plausible that another beheading happened. Still, you need to cite a source. You need to make more probes before it's put out on a news service."

Vanderford, a San Francisco musician and video game designer who briefly mounted a campaign for the San Francisco Board of Supervisors this year, spent Saturday in his Western Addition high-rise apartment and said through friends that his attorney had advised him to stop talking about the video hoax.

But Martin and Kirchner, who were visiting Vanderford to offer their support, agreed to talk about their short film "to clear up misconceptions."

"We made the film in my garage in Pleasanton," said Martin, who described himself as an experimental musician. "We made the fake blood with corn syrup and red food coloring -- a recipe that we got on the Internet. We used a low- level cheap digital video camera. And if you look closely at the video, you see the supposed beheading is done with a dull vegetable knife and we used the wrong side. ... We did the whole thing in a couple of hours."

Kirchner said the concept behind the hoax was to show how easy it is to make something fake look real. She and her two fellow filmmakers, she said, wanted to challenge others to question the validity of material that is presented as fact.

"What is amazing,'' she said, "is the power of the Internet. One person gets the file, they share it with someone else. It eventually ends up on some Arab TV station and is believed as the real thing."

Hours after it posted the clip, the Islamic Minbar site had removed it and posted a statement saying that it was checking its other videos of beheadings to make sure there were no other frauds.

Both Vanderford and Martin were interviewed by FBI agents Saturday. San Francisco FBI spokeswoman LaRae Quy said the FBI is working with local law enforcement and the U.S. Attorney's Office to determine whether any charges can be filed against Vanderford.

"It's a very unusual situation," Quy said. "It may come down to freedom of speech, and we'll defer to the U.S. attorney's office here on that. The question is: At what point does he step from freedom of expression into something that makes a mockery out of the pain suffered by families that have had beheadings of loved ones?"

For those who have lost relatives to the violence of Islamic militants, the beheading hoax seemed thoughtlessly cruel.

"The person who did this can't have a heart," said Bruce Hauser, who lives next door to Michael and Suzanne Berg, Nicholas Berg's parents. Berg's beheading was captured on video and later shown on the Internet.

Hauser, a close friend who became the Berg family spokesman after Nicholas was killed, said from his home in Philadelphia that he sees the raw grief that comes with loss. For the Berg family, the grief hasn't abated, he said.

"The world needs to keep in mind there are families like the Bergs that are going through this suffering," Hauser said. "It is all too real for them."

When told of Hauser's statement, Martin and Kirchner expressed regret for any harm caused by their hoax. "If any families, such as the families of Daniel Pearl or Nicholas Berg have been caused undue stress, we apologize," said Kirchner. "It's not our fault. It's the media that made this real. This was intended to be a ridiculous little parody."

E-mail the writers at bwallace@sfchronicle.com and jguthrie@sfchronicle.com.

Commentary:
Real Journalists verify what they say before they report it. Fools like the AP, Reuters, Fox, CNN, ABC, NBC, CBS and every newspaper in the country forgot how to do that. Since it's this easy to fool every news organization in the country, imagine how easy it is to manipulate us using the most sophisticated propaganda machine ever created (otherwise called the "White House Press Office").

The solution is to require journalists to verity what they say before they say it and when they don't, fire them. One obvious problem with my solution is that our news channels and papers would be empty.