Dirty bomb: Brooklyn-born suspect turned to Islam while serving 12-month jail sentence

The man destined to be dubbed the would-be "Dirty Bomber" is a former member of a Chicago street gang who converted to Islam while serving a one-year jail sentence within an American prison.

Abdullah al-Mujahir, 31, formerly known as Jose Padilla, is a US citizen with a US passport. Reports from US law enforcement sources say that in the early 1990s he was a member of a gang operating within the city of Chicago, Illinois. In the early 1990s, possibly 1991, Mr al-Mujahir was jailed – believed to be for 12 months – and that during his incarceration he became interested in Islam.

Details about Mr al-Mujahir – who is being held at the Consolidated Naval Brig in Charleston, South Carolina – are far from complete. It is believed he was born in Brooklyn, New York, and that he moved to Chicago at the age of four or five. His arrest in the early 1990s was believed to be over weapons offences.

The US Attorney General, John Ashcroft, said Mr al-Mujahir had travelled to Afghanistan and Pakistan during 2001 and met with al-Qa'ida officials. Mr Ashcroft said he "trained with the enemy, including studying how to wire explosive devices and researching radiological dispersion devices". Other sources said he also spent time in the Middle East and that on at least one occasion he met with Abu Zubeida, a senior al-Qa'ida figure currently in US custody at Guantanamo Bay and whose interrogation has apparently led to Mr al-Mujahir's arrest.

Mr al-Mujahir first met Mr Zubeida – the man who was being groomed to take over the leadership of al-Qa'ida from Osama bin Laden – in Afghanistan in 2001, and then travelled with him to Pakistan. At Mr Zubeida's request he also travelled to the Pakistani city of Karachi to meet with senior al-Qa'ida operatives, to discuss the plan.

One US official said they talked about plans to bomb hotel rooms and petrol stations within America.

Mr Ashcroft said that al-Qa'ida may have been particularly keen to recruit Mr al-Mujahir because he owned a US passport and could therefore travel more easily within the country than other members of the terror network.

Mr al-Mujahir was arrested on 8 Mayat Chicago's O'Hare International Airport, coming off a Kuwaiti Airlines flight from Pakistan. He was being held on a federal warrant in New York. With last night's deadline for the authorities to charge or release Mr al-Mujahir approaching, he was named an "enemy combatant" and transferred to the custody of the Defence Department. Officials admitted this was done so he could be held longer without charge.

Mr Muhajir and two suspected accomplices were stopped in Pakistan before boarding the flight and only he was allowed to board, believing he had "escaped". In fact US agents were sitting on the plane monitoring him.