U.S. Customs and Border Protection officers searched Bieber's private airplane -- thought to be the one pictured -- January 31, 2014, at Teterboro Airport in New Jersey. Officers said they detected an odor of what seemed like marijuana after the plane landed, law enforcement sources told CNN. Drug-sniffing dogs were used to search the plane, according to one of the sources, but no sign of drugs were detected and no illegal substances were found. The investigation was closed in July.