the most wanted woman in the world; How did a Boston-educated scientist and mother of three end up on the FBI's list of possible top al-Qaeda terrorists.

Byline: Deborah Scroggins

Aafia Siddiqui, a 33-year-old Boston neuroscientist and the mother of three young children, became the most wanted woman in the world on May 26, 2004. That was the day U.S. Attorney General John Ashcroft strode onto a Washington podium lined with gigantic black-and-white mug shots of Aafia and six Muslim men. Standing there, Ashcroft grimly warned the American people that every one of the individuals pictured could be involved in a plot to "hit the United States." "They're all sought in connection with terrorist threats against the United States," he intoned in typically sonorous fashion. "They all pose a clear and present danger to the U.S. They all should be considered armed and dangerous." With black hair severely pulled back and her mouth set in an uncompromising line, the diminutive Aafia looked at least as menacing in her FBI photo as the others, and U.S. officials soon were saying privately that the only woman officially named as an al-Qaeda operative might well be the most threatening of them all.

I'd first heard of Aafia more than a year earlier, around the time she suddenly vanished along with her children from her hometown of Karachi. That was when Washington started issuing warnings, often mentioning her by name, about the possibility that al-Qaeda might start using women in its attacks and that those attacks might involve chemical weapons or even a dirty bomb. With degrees from Brandeis University and the Massachusetts Institute of Technology, she was said to be one of the few alleged al-Qaeda associates with the ability to move about the United States undetected and the scientific expertise to carry out a sophisticated attack. U.S. officials said she and her ex-husband, a former anesthesiologist at Boston's Brigham and Women's Hospital, had made suspicious money transfers and purchases of military equipment on the Internet. More ominously, they claimed that she had helped the mastermind of the 9/11 attacks, Khalid Sheikh Mohammed, with a plot to blow up underground gas tanks around Baltimore.

Aafia's friends and relatives vehemently disputed everything about the FBI's picture of her, including the photo itself, which they said was a composite drawn up from her Massachusetts driver's license to make her look as if she were a terrorist. "It just seems so unlikely," said Salma Kazmi, a Boston resident who knew Aafia from her student days. "I mean, she was just a mom!" In Boston, her family enlisted Elaine Whitfield Sharp, who first gained national fame as the attorney who defended British nanny Louise Woodward against charges of accidentally killing a baby in her care, to stress that Aafia had not been charged with any crime and was only wanted by the FBI for questioning. Sharp said Aafia's ex-husband had beaten her and their children and might have had a hand in their disappearance. She added that the Siddiqui family had not seen Aafia since she got into a minicab in March 2003 accompanied by her six-year-old son, three-year-old daughter, and six-month-old baby boy, and were desperately worried about all four of them.

Then, some ten weeks after Sharp's press conference, came another thunderclap. Witnesses at a United Nations war-crimes-tribunal meeting in the African nation of Sierra Leone identified Aafia Siddiqui as the woman who had visited Liberia in the months before the 9/11 attacks to oversee a $19 million diamond deal on behalf of al-Qaeda. Aafia Siddiqui, the witnesses seemed to be saying, wasn't just an "operator and facilitator"-she was the Mata Hari of al-Qaeda.

In fact, as I discovered on a search that took me from the teeming cities of Pakistan to the chilly banks of Boston's Charles River, the truth about Aafia Siddiqui may be both more ordinary and more frightening than has been previously reported. Hers is the story of an idealistic young woman who made the journey from Muslim student activism to possibly helping al-Qaeda terrorists bent on global jihad. But for the fact that she's a woman, her profile is not so different from that of others who have been drawn into al-Qaeda's web. Like many of them, she's a well-bred, computer-savvy professional educated in the West. As General Hamid Gul, the former head of Pakistan's intelligence agency, put it, "These are not riffraff-these are the cream of society." Her story sheds light on what psychiatrist and former CIA analyst Marc Sageman calls "the neglected role of women" in motivating men to fight for radical Islamic causes. And the mystery of her disappearance offers a peek into a secret war against terror that both U.S. and Pakistani officials would prefer to keep in the shadows.

Aafia Siddiqui was born in 1972, the youngest of three children, to Mohammed Siddiqui, a physician, and his wife, Ismat, an Islamic teacher and charity volunteer. After training in Britain, Siddiqui brought his family back to Karachi, a once-sleepy fishing village that has grown into a sweltering megalopolis of 14 million. They settled into a large, white, bougainvillea-draped bungalow in the exclusive "E" section of the Gulshan-e-Iqbal neighborhood. By all accounts, Aafia's was a happy childhood, filled with pets and dolls. Her sister, Fowzia, says she was an obedient little girl, eager to please because "she could not bear being yelled at."