One day in the winter of 1996, while 12-year-old Suad Leija was getting ready for school, more than a dozen armed FBI agents raided her family's Chicago-area home. They were looking for her stepfather, Manuel Leija-Sanchez, who federal authorities believe runs a document-fraud network -- producing fake passports, Social Security cards, driver's licenses and a variety of other official papers -- with cells throughout the United States. That cold morning, the agents were too late. Manuel Leija-Sanchez had fled during the night to Mexico after he was tipped off to the impending raid, his stepdaughter recalled. The business continued to...