Byline: Evan Thomas and Mark Hosenball

Frustrated sons of privilege, caught between East and West, sometimes make for dangerous militants. Mohamed Atta, the lead 9/11 hijacker, was the son of a Cairo lawyer and the grandson of a doctor. The so-called underwear bomber, Umar Farouk Abdulmutallab, is the son of a wealthy Nigerian diplomat. Faisal Shahzad, too, appeared to be a fairly secularized, Westernized Pakistani. His father was once a high-ranking official in Pakistan's Air Force, and Faisal had become a U.S. citizen. But unknown to many who knew him superficially, his life was riven by tensions that propelled him toward terrorism.

That Shahzad failed in his attempt to set off a lethal fireball in Times Square this month was reassuring, but not very. The FBI and New York City police were able to capture the alleged bomber in part because the 30-year-old Shahzad was a bungler when it came to building bombs. Unfortunately, there are more would-be terrorists like him out there, and terrorists learn from their mistakes. Al Qaeda may be on the run and (possibly) not capable of pulling off a 9/11-style spectacular, but various wannabe and splinter terror groups seem to be able to attract recruits with American passports and the will to kill civilians, if not quite the know-how.

Americans demand that the government keep them safe from the Shahzads of the world. Yet it is not always easy to spot an alleged terrorist in the making, at least not at first. Like most Pakistanis his age, Shahzad had received rigid Islamic schooling, instituted by the Pakistani government in the 1990s. And like a good number of privileged young Pakistanis, he was sent to the West to further his education. He picked up a business degree at the University of Bridgeport in Connecticut and got a job managing accounts at Elizabeth Arden, the cosmetics maker, in the affluent town of Stamford. He and his new wife, Huma Mian, who has a degree from the University of Colorado, bought a house in the Connecticut suburbs for $273,000. Shahzad got a job as an analyst at Affinion Group, a financial-marketing-services company, in 2007--just as the market bubble was about to burst. He became an American citizen.

He appeared to develop money troubles. Friends noticed that he began talking more about Islam, and he frequently traveled back and forth to Pakistan. Last year he and his young family suddenly abandoned their house, leaving behind rotting food and toys. The house went into foreclosure.

Last week Newsweek interviewed Shahzad's cousin Zulfikar Ali, a bank employee in Peshawar, who said that in recent months Shahzad didn't seem like the same person he knew when he was younger. Ali described Shahzad's family as not being particularly religious. "The father ran a disciplined family," he said. "The father really kept Shahzad under his thumb." Ali, who said he had met Shahzad at least 10 times in the past few years, last saw him six months ago at a family wedding in Mohib Banda village. He was very different. As a younger man, Ali said, Shahzad was polite, well mannered, and enthusiastic about his studies. "I was never suspicious of him," he recalled. But when Ali saw him at the wedding, Shahzad seemed to have changed. "He seemed more serious, quiet, and distant," Ali said. Ali wondered whether Shahzad's embrace of militancy could have partly been a revolt against his father's military-like strictness.

When Shahzad came back to America in February after a five-month visit in Pakistan, he was alone. His wife and child remained behind. He rented an apartment in a gritty blue-collar neighborhood in Bridgeport and began making some suspicious purchases, including more than 150 firecrackers, some bags of fertilizer, and a couple of alarm clocks. Consulting Craigslist, he bought a used SUV--a Nissan Pathfinder big enough for a bomb--for $1,300 cash, paid in $100 bills. No papers changed hands. He had the windows tinted so no one could see in and removed the vehicle-registration number from the dashboard. …