 On July 4, Mihdhar returned to the United States, arriving at New York City's John F. Kennedy International Airport, using a new passport obtained the previous month.A digital copy of one of Mihdhar's passports was later recovered during a search of an al-Qaeda safe house in Afghanistan, which held indicators, such as fake or altered passport stamps, that Mihdhar was a member of a known terrorist group.At the time when Mihdhar was admitted to the United States, immigration inspectors had not been trained to look for such indicators.