Like some of al Qaeda's most notorious members, the Pakistani-American charged in connection with the botched bomb in New York's Times Square comes from a respectable background that provides no hints of radicalism.
Faisal Shahzad, a naturalised American, has admitted to trying to detonate the bomb in a sports utility vehicle and receiving explosives-making training in a known Taliban and al Qaeda stronghold in Pakistan, US prosecutors say.
On the surface, he bears no resemblance to the many impoverished Pakistani men who have been lured to the Taliban by promises of holy war and martyrdom.
Shahzad, a former financial analyst who worked in the US state of Connecticut, is the son of a retired vice air marshal, affording him a special status in Pakistan, where the military is the most powerful and influential institution.
His brother is a mechanical engineer in Canada, Pakistani security officials said.
The United States and Pakistan will now try to study Shahzad's path to Times Square, how he ended up in a militant training camp in Pakistan and which group influenced him, information they hope will help prevent future attacks.
Security officials say Shahzad's parents resided in Peshawar, the city hit hardest by Pakistani Taliban suicide bombings. They said Shahzad also has a residency identification card from commercial hub Karachi.
On Tuesday in Karachi, Pakistan detained several associates of Shahzad, including friends and members of his extended family, officials said.
Pakistani Interior Minister Rehman Malik said Shahzad's family "are on our radar".
"He is not from a radical or illiterate family. He is from an educated family. We are looking into how he got radicalised," he told Reuters.
But there are plenty of examples of people with a respectable past who turned to jihad.
Take al Qaeda leader Osama bin Laden, who hails from Saudi Arabia's elite, or his Egyptian deputy Ayman al-Zawahri, born into an upper-class family of doctors and scholars in an upscale Cairo neighbourhood.
Mohammed Atta, leader of the 9/11 hijackers, enrolled as a graduate student of urban planning at a technical university in Germany.
Aside from struggling against a Taliban insurgency, Pakistan also faces threats from foreign would-be jihadis trying to link up with Pakistani militants through the Internet.
In March, a Pakistani court formally charged five young Americans of plotting terrorism in the country.
The students, in their 20s and from the U.S. state of Virginia, were detained in December in the town of Sargodha, 190 km (120 miles) southeast of Islamabad.
Pakistan, a US ally, has in the past nurtured militant groups to fight in Indian-controlled Kashmir and mujahideen to fight Soviet occupation troops in Afghanistan.
After the September 11, 2001 attacks on New York's Twin Towers and the Pentagon in Washington, Pakistan, under enormous American pressure, joined the US war on terror, although questions have arisen about its level of commitment.