Defendants were U.S. citizens and had already crossed the border. The car had Louisiana plates. They were stopped at the Falfurrias Border Patrol checkpoint and citizenship was quickly resolved, but reasonable suspicion developed for the car to be referred to a secondary checkpoint. United States v. Knight, 2017 U.S. Dist. LEXIS 28442 (S.D. Tex. March 1, 2017):
When Agent Cantu referred Defendants to secondary inspection, he had already determined that they were United States citizens so the immigration-related justification for the stop had ceased. However, the facts articulated by Agent Cantu—Knight’s initial failure to stop for inspection, avoidance of verbal answers, and stuttering; DeSoto answering the question for Knight; and Defendants’ actions indicating nervousness (shaking hands and fidgeting)—were, when considered together, sufficient for Agent Cantu to believe that criminal activity was afoot. Thus, the Court finds that the further detention in secondary inspection was justified by reasonable suspicion.