Najibullah Zazi in Aurora, Colo.

Aurora
The heartland suburb where Zazi chose to live lies at the edge of the Colorado plains. It is a vast city — nearly 154 sq. mi. — with a population of 315,000 people, including dozens of immigrant communities. It is, in short, an excellent place for a young man with a laptop and a recipe for bombs to hide.

• An Enemy Within: The Making of Najibullah Zazi