An American journalist named Brian McWilliams fooled his fellow journalists on Wednesday, by posing on the Internet as the terrorist group Harkat-ul-Mujahideen (HUM). He also fooled the U.S. Government.

McWilliams registered the domain HarkatUlMujahideen.org in early 2002, as part of a plan for investigating radical Islam. The domain pointed to a counterfeit HUM web site created by the journalist. The site successfully attracted terrorists to the reporter, who says he intended to compile and report on his findings. The real HUM has been on the United States' list of foreign terrorist organizations since 1997.

Then, last weekend, nearly a year after the birth of his web site, McWilliams took his illusion one step further. He took on the identity of a fictitious HUM terrorist called "Abu Mujahid." He claimed that HUM was responsible for the recent Microsoft SQL "Slammer" worm, and that it was part of a new wave of "cyber jihad."

A reporter and former U.S. military intelligence analyst named Dan Verton was quick to contact "Mujahid" about his claims. Despite the fact that Mujahid's emails came from the United States, and that McWilliams had written openly about the domain before, Verton decided that he had found a credible source. Credible enough that on Wednesday he published a story in Computerworld called "Terrorist group claims responsibility for Slammer worm." (The article has since been removed from Computerworld.)

The National Infrastructure Protection Center (NIPC), the United States' supposed first line of defense against cyber-attack, also analyzed McWilliams' terrorist ruse. Like Verton, they too concluded that the phony HUM was real.

Verton told the Associated Press that he had fallen victim to "an elaborate scheme to dupe security companies and journalists."

McWilliams has now apologized to his colleagues, but his point is clear. "As my bungled experiment proved, even Verton... can apparently be fooled by fake e-mails, phony web sites, and wild claims, in a desire to get a big scoop on a hot topic," McWilliams wrote.

In the biggest scoop of all, the United States' Homeland Security Advisory System was upgraded on Friday to Threat Level Orange.