Less than 72 hours after a Nissan Pathfinder rigged to blow was found in Times Square, U.S. authorities had arrested Faisal Shahzad and charged him with terrorism.
Understanding what made a young, middle-class American father who frequented Red Lobster turn to violence will take longer.
"I was expecting you," he reportedly told the border control officers who boarded the plane to take him into custody. "Are you NYPD or FBI?"
Dissecting how people like Mr. Shahzad reach a point where they're prepared to act on an extremist ideology is an increasingly urgent task for those who study terrorism.
Plots by U.S. citizens acting alone - Mr. Shahzad has so far claimed to be the sole perpetrator - are extremely difficult to detect. Infiltrating extremist groups won't necessarily catch such would-be terrorists, nor will monitoring cross-border communications.
Several aspects of Mr. Shahzad's story are familiar to those who have studied groups of Western Muslims in thrall to violent extremism. Like a number of such individuals, Mr. Shahzad's background is hardly one of dire poverty. Both he and his wife grew up in prosperous, well-educated families in Pakistan. His father was a senior air force official; hers is an oil executive.
What's more, he appeared to be living a perfectly ordinary life. The New York Police Department studied local residents or citizens who had plotted violence against cities in the United States and Europe and found the majority were "unremarkable" - they held normal jobs and had little if any criminal history.
The common theme, experts have shown, is a gradual rather than sudden evolution toward radical views and later violence. Marc Sageman, a psychiatrist and former CIA officer who studies terrorist networks, says it often begins with a sense of grievance, and likens the embrace of fundamentalist views to joining a counterculture of protest.
Later, morally outraged by events - the wars in Iraq and Afghanistan, for instance - individuals start to believe the existing approach is ineffective and begin to feel a personal duty to take things into their own hands.
Dr. Sageman adds that it's too soon to know whether Mr. Shahzad fits that pattern. He says he wouldn't describe Mr. Shahzad as a "homegrown" radical since he didn't grow up in the United States and appears to have visited Pakistan several times. "I don't really know whether this guy radicalizes here or radicalizes there," Dr. Sageman said.
He said Mr. Shahzad's tale shares some elements with that of Najibullah Zazi.
Like Mr. Zazi, Mr. Shahzad is apparently Pashtun, a major ethnic group in the tribal belt of Pakistan and the bordering areas of Afghanistan. Mr. Zazi came to New York as a teenager, and last year he was arrested for plotting a suicide bomb attack on the city's subway after receiving explosives training in Pakistan.
Early indications are that Mr. Shahzad wasn't particularly devout. His family shopped at a halal butcher but he didn't frequent the largest nearby mosque.
Studies have found that religious fervour or considerable religious education is not a precondition for radicalization. "There's this notion that the more religious you are, the more radical you are," says David Schanzer, director of the Triangle Center on Terrorism and Homeland Security at Duke University. "We think that's not true."
The leap from fundamentalist beliefs to a willingness to engage in violence often takes place through socializing with like-minded people, scholars say, though that can happen either in person or online. Many extremist groups use the internet as a tool for self-promotion and recruitment.
It's unclear whether such online gateways to fundamentalism played any role with Mr. Shahzad. So far his Internet browsing habits appear like those of any young professional, featuring visits to social networking sites such as Facebook and Orkut. In one photo posted on Orkut, he gives a muted smile to the camera as he cradles a newborn infant.
Bruce Hoffman, a terrorism expert and professor of security studies at Georgetown University, says that Mr. Shahzad's story feels similar to ones that have unfolded in Britain. There, a number of the young men who became violent radicals were educated, middle-class, and well-integrated into the larger society, at least superficially. A trip to the land of their birth - or where their family is from - often played a huge role in the radicalization process.
Whatever the turning points on Mr. Shahzad's road to Times Square on Saturday night, the fact that he arrived there without arousing any kind of suspicion is part of a worrisome pattern, Prof. Hoffman said.
"In the U.S., we're very good at reacting," he said. "The challenge in the future is how we're going to get our arms around identifying radicalization and interdicting recruitment."