The FBI “most wanted” mugshot shows a tough, swarthy figure, his hair in a jailbird crew-cut. The $10 million price on his head, meanwhile, suggests that whoever released him from US custody four years ago may now be regretting it.Taken during his years as a detainee at the US-run Camp Bucca in southern Iraq, this is the only known photograph of Abu Bakr al-Baghdadi, the new leader of al-Qaeda in Iraq and Syria. But while he may lack the photogenic qualities of his hero, Osama bin Laden, he is fast becoming the new poster-boy for the global jihadist movement.Well-organised and utterly ruthless, the ex-preacher is the driving force behind al-Qaeda’s resurgence throughout Syria and Iraq, putting it at the forefront of the war to topple President Bashar al-Assad and starting a fresh campaign of mayhem against the Western-backed government in Baghdad.Osama bin Laden, he is fast becoming the new poster-boy for the global jihadist movement.On Tuesday, his forces achieved their biggest coup in Iraq to date,seizing control of government buildings in Mosul, the country’s third biggest city. Coming on top of similar operations in January that planted the black jihadi flag in the towns of Fallujah and Ramadi, it gives al-Qaeda control of large swathes of the north and west of the country, and poses the biggest security crisis since the US pull-out two years ago.But who is exactly is the man who is threatening to plunge Iraq back to its darkest days, and why has he become so effective?As with many of al-Qaeda’s leaders, precise details are sketchy. His FBI rap sheet offers little beyond the fact that he is aged around 42, and was born as Ibrahim Ali al-Badri in the city of Samarrah, which lies on a palm-lined bend in the Tigris north of Baghdad. Abu Bakr al-Baghdadi is a nom de guerre, as is his other name, Abu Duaa, which translates roughly as “Father of the Summons”.Some describe him as a farmer who was arrested by US forces during a mass sweep in 2005, who then became radicalised at Camp Bucca, where many al-Qaeda commanders were held. Others, though, believe he was a radical even during the largely secular era of Saddam Hussein, and became a prominent al-Qaeda player very shortly after the US invasion.“This guy was a Salafi (a follower of a fundamentalist brand of Islam), and Saddam’s regime would have kept a close eye on him,” said Dr Michael Knights, an Iraq expert at the Washington Institute for Near East Policy.“He was also in Camp Bucca for several years, which suggests he was already considered a serious threat when he went in there.”That theory seems backed by US intelligence reports from 2005, which describe him as al-Qaeda’s point man in Qaim, a fly-blown town in Iraq’s western desert.“Abu Duaa was connected to the intimidation, torture and murder of local civilians in Qaim”, says a Pentagon document. “He would kidnap individuals or entire families, accuse them, pronounce sentence and then publicly execute them.”Why such a ferocious individual was deemed fit for release in 2009 is not known. One possible explanation is that he was one of thousands of suspected insurgents granted amnesty as the US began its draw down in Iraq. Another, though, is that rather like Keyser Söze, the enigmatic crimelord in the film The Usual Suspects, he may actually be several different people.