Even if he is proven to be the aspiring terrorist the government asserts, how and why he became one may not be understood for months, if ever. The suspects who have been charged with terrorism since the Sept. 11 attacks were fueled by a variety of motivations and influences, and often a mix of them: politics, family, economic deprivation, social alienation, the work of a terrorist recruiter. Religion sometimes provides a general framework and sense of identity, but other factors and events frequently drive the transformation.

For nearly two weeks, though, the story of Mr. Zazi, now one of national interest, has lacked almost any details. A tour of where Mr. Zazi worked and lived, in New York and in Colorado, and interviews with investigators, the Zazi family and friends, provides something of a fuller picture, one filled with the routines of life in Queens but also flecked with hints of his emerging anger, contradictions and puzzles.

Mr. Zazi is both an Afghan immigrant steeped in the traditions of Islam and a kid from the streets of Queens, where his family moved in the early 1990s.

As a teenager, he often carried two things, his basketball and his prayer mat, his friends say. He grew a dark, wiry beard and began wearing tunics several years ago, just as he was applying for his first of two Macy’s credit cards.

He was a janitor and a worshiper at a mosque that split several years ago over the question of its members’ loyalty to the Taliban after the Sept. 11 attacks. He was a devoted fan of gadgets who married, by arrangement, his 19-year-old cousin, who lives with their two children in Pakistan.

Last summer, the authorities say, he shopped in Denver for hair supplies to build bombs with. If he did so, he was also engaged in something much more mundane: credit counseling to survive a bankruptcy he had declared in New York.

It is impossible at this moment to know what it all adds up to. But the details that are being learned create the sense of a far more complicated man than the coffee cart vendor many people saw. Certainly the government’s charges have painted the outlines of a man Mr. Zazi’s family is having a very difficult time reconciling with the Najib they knew.