As Iraq prepares what it boasts will be its "decisive battle" against al Qaeda, government forces face the challenge of tracking its shadowy leader, whose very existence has been called into doubt.
Within the virtual world of extremist Internet propaganda, Abu Omar Al-Baghdadi is leader of the Islamic State of Iraq, an umbrella organisation for al Qaeda affiliated insurgent groups fighting US and Iraqi forces. But for American commanders he's a confidence trick, a straw man invented to put an Iraqi face on a terrorist group led by foreigners who infiltrated Iraq to sow chaos and undermine the US-backed government.
"We have seen no pictures of him. We don't have irrefutable evidence that he actually exists, but we don't discount that there may be a man named Omar al-Baghdadi," a US military intelligence officer told reporters last month.
"It is clear that if he does exist he has little influence within the al Qaeda hierarchy and that he is not responsible for all the things claimed in his name. This guy is a figurehead," he said on condition of anonymity. Abu Omar's story began in October 2006, when al Qaeda announced in an Internet statement the founding of the so-called Islamic State of Iraq, a virtual caliphate which was supposed to unite Sunni insurgent factions.
On the model of Afghanistan's former Taliban regime, the group would be led by an Amir al-Muminin or "Commander of the Faithful", in this case a little known figure called Abu Omar al-Baghdadi - "Omar's Father from Baghdad". Previously, he had been said to run the legal department of another supposed insurgent coalition, empowered to issue fatwas or rulings based on Islamic Sharia law deciding, for example, the fate of al Qaeda hostages.
In May 2007, Iraqi officials declared that Abptive Iraqi al Qaeda member, Khaled al-Mashhadani, who allegedly served as an intermediary between the movement's Iraqi affiliate and its global figurehead, Osama bin Laden.
Mashhadani had been arrested on July 4 and had revealed to his US captors that the Islamic State was nothing more than a story invented to mask the identity of the group's real - foreign - leaders, Bergner said.
Abu Omar's voice on recorded statements boasting of al Qaeda's violent operations in Iraq had been played by an Iraqi actor, Abdullah al-Naima, the American spokesman said. For US commanders, the real leader of al Qaeda in Iraq is one Abu Hamza al-Muhajir - better known as Abu Ayyub al-Masri or "Ayyub's Father the Egyptian" - who is "minister of war" in the so-called caliphate.
Reportedly an expert bomb maker, the Egyptian militant was named leader of al Qaeda in Iraq in June 2006 following the death of his better-known Jordanian predecessor Abu Musab al-Zarqawi in an American air strike.
In November 2006, in a recorded communique, Abu Ayyub swore allegiance to Abu Omar and the Islamic State, a move which Bergner has since dismissed as a ruse to conceal his continued leadership of the movement. In 15 months at the head of his so-called caliphate, the commander of the faithful has released at least seven audiotapes and has been addressed as the leader of al Qaeda's Iraqi operation by Bin Laden himself.
Most outside experts agree with the Americans that the Egyptian is still the leading al Qaeda figure in Iraq, but the mystery of Abu Omar continues and some are not so quick as to dismiss him has non-existent.
"Abu Omar exists physically, and is without a doubt an Iraqi," says Middle East expert Jean-Pierre Filiu from the Institut d'Etudes Politiques in Paris. "But his identity means very little, as his anonymity helps protect him and boost his presence in cyberspace. The power within al Qaeda in Iraq is in the hands of non-Iraqis."