Threats and Murder Update from MEMRI, with thanks to Suzie:
Purported “Al-Qaeda Undercover Soldier, U.S.A”: Last Warning to American People – Two Operations Will Occur; Your Homeland Security Agency Must Surrender; States Far Away From Washington, D.C. Such as Arizona Will Be Hit; We Await Orders From Our Commander Osama Bin Laden; America Will Be Brought to its Knees
On March 10, 2006, the Global Islamic Media Front (GIMF) posted, on the Islamic websites, a final warning to the American people, on behalf of “Rakan Ben Williams” who defines himself as “Al-Qaeda under cover soldier, USA [sic].”
It is not clear exactly who is behind this name. Moreover, according to a previous statement by GIMF public relations bureau director Saif Al-Din Al-Kinani on the GIMF Internet newscast Sout Al-Khilafa, GIMF is not affiliated with Al-Qaeda. 
But on November 8, 2005, the London daily Al-Sharq Al-Awsat reported: “The Global Islamic Media Front has threatened [the West] on the Internet by means of its new soldier, whom it calls Rakan Ben Williams, and whom it claims is a white Englishman who converted to Islam.” 
Also, on November 24, 2005, the GIMF posted on the Islamic websites a similar warning, under the same name, that included an explicit threat to assassinate Italian Prime Minister Silvio Berlusconi, Australian Prime Minister John Howard, Japanese Prime Minister Junichiro Koizumi, British Prime Minister Tony Blair, and U.S. President George W. Bush, when the time comes, with a clear mention of the possibility of doing so after they complete their current terms of office. Although this communiquÃ© was directed to these leaders, it noted that it referred to all Western leaders, and included special mention of Berlusconi. At its conclusion, the communiquÃ© said that it had been written by “the one who thirsts for the blood of the Crusaders, the secret soldier of Al-Qaeda, Rakan Ben Williams, Italy (the Vatican).” 
In the following warning, Rakan Ben Williams warns that, unlike after the 9/11, Madrid, and London attacks, which are still being investigated, “[after] the coming attack there will be no one to analyze and investigate, because the mind and the heart will be unable to comprehend it”¦ This will not be a single operation”, the report added, “but two; one bigger than the other, but we will begin with the big one and postpone the bigger one, in order to see [how] diligent the American people is [in preserving] its life. If it chooses life, [it must] carry out the demands of the Muslims, and if it chooses death, then we are its best perpetrators.” The warning appeared in Arabic and in English.
At the MEMRI link are excerpts from the original.