Sepulveda-Barraza

Alejandro Sepulveda-Barraza appeals his conviction for importation of cocaine and possession with the intent to distribute, claiming that the district court erred in admitting expert testimony regarding the structure and operations of drug-trafficking organizations and drug couriers, including testimony that drugs are rarely smuggled by unknowing couriers. We hold that the district court did not abuse its discretion in admitting this testimony, *1077 because it was relevant, probative, and not unduly prejudicial in light of Sepulveda-Barraza’s defense theory that he did not know that he was transporting drugs.

I

On September 11, 2007, Sepulveda-Barraza was stopped by government inspectors at a port of entry in Nogales, Arizona. He claimed that he was driving across the border to run errands at Wal-Mart, but was only carrying $21 in United States currency. Because he seemed a “little nervous” and a “little too friendly,” an inspector referred him for secondary inspection. At secondary inspection, officers discovered eleven packages of cocaine hidden in the seats of his vehicle.

A grand jury indicted Sepulveda-Barraza on one count of importation of cocaine in violation…