US intelligence officials are now beginning to believe that a woman, some sources described as 'the Al Qaeda chick', may have helped planned logistics, but was not a major participant in the terror network's activities.

Dr Aafia Siddiqui (31), an alumna of the Massachusetts Institute of Technology (MIT), was detained in Karachi on March 29 as soon as she returned from an overseas trip.

Sources told rediff.com that her links to Al Qaeda had been corroborated by the outfit's operations chief Khalid Shaikh Mohammad, currently in the custody of US law enforcement officials after his arrest in Karachi a few weeks back.

Siddiqui, who has a doctorate in neurological science, is a mother of three and lived in Boston with her spouse before she disappeared.

US intelligence had received information from a variety of sources that Al Qaeda may have a female operative helping out with logistics planning.

They were told that she was not an operative of the kind of Adnan El Shukrijumah, the 27-year-old Saudi national suspected of plotting terrorist attacks in the United States, but was considered 'more of a support person' for Shukrijumah and it is 'likely she may have accompanied him' during his travel in the US.

Intelligence agencies were told she moved money for Al Qaeda operatives and was also involved with radical groups in Pakistan, particularly in the Northwest Frontier Province.

When Siddiqui's name first cropped up, intelligence agents suspected it may have been a new strategy of the Osama bin Laden-led terrorist group, because few would imagine an American-educated woman with children ranging from the age of nine months to six years to be working for Al Qaeda.

Once she became the first woman wanted by the FBI for questioning on suspicion of having links with the Al Qaeda, it posted two pictures of her on its web site, one with and one without the hijab, the head-covering scarf worn by some Muslim women.

The agency said she wore both traditional Pakistani and Western clothes and could be travelling with or without her children.

Following up reports in December and January that placed her in Gaitherberg, Maryland, a suburb of Washington DC, authorities started looking for her on the eastern seaboard, according to Gary Bald, special agent in charge of the FBI's Baltimore field office.

On March 18, the FBI issued a worldwide search notice for Siddiqui after Shaikh Mohammad confirmed her links to Al Qaeda.

She was tracked down to the home of her relatives in Karachi after being tailed from the Quaid-e-Azam International Airport where she was spotted on arrival from an overseas trip.

Pakistani authorities were immediately directed to arrest her.

Siddiqui was being interrogated at an undisclosed location, but intelligence sources said she is yet to be charged with any crime.

"She's essentially in the hands of the FBI now," said the source, who refused to reveal if she has been flown out of Pakistan for interrogation.