United States v. Flores-Montano

Supreme Court of the United States · 2004 · Criminal Procedure

541 U.S. 149 (2004)

Updated July 27, 2026

Criminal ProcedureFourth AmendmentBorder Searchesborder searchinternational bordervehicle searchfuel tankreasonable suspicion

Facts

Respondent attempted to enter the United States from Mexico in a 1987 Ford Taurus station wagon at the Otay Mesa Port of Entry. After initial inspection, customs officers sent the car to secondary inspection, where an inspector tapped the gas tank, thought it sounded solid, and summoned a mechanic to remove it. The mechanic removed the tank, disconnected hoses and electrical connections, and after the tank was off, the inspector removed bondo from the top, opened an access plate, and found 37 kilograms of marijuana. The process took about an hour total, including a 20-to-30-minute wait for the mechanic and 15 to 25 minutes for the removal procedure itself.

Issue

Does the Fourth Amendment require reasonable suspicion for customs officials at the international border to remove, disassemble, and reassemble a vehicle's fuel tank during a border inspection? More specifically, is such a gas tank search a type of vehicle border search that customs may conduct without individualized suspicion?

Rule

At the international border, the Government may conduct suspicionless inspections of vehicles, and that authority includes removing, disassembling, and reassembling a vehicle's fuel tank. The Court rejected using a 'routine' versus 'nonroutine' intrusiveness balancing test for vehicle border searches, while leaving open that some searches of property so destructive or offensively carried out might require a different result.

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One of 10 multiple-choice questions for this case. Pick an answer to see why.

At the international bridge in El Paso, customs officers stopped Nina Alvarez as she drove a sedan into the United States from Mexico. Without any individualized suspicion, officers sent the car to secondary inspection, removed the fuel tank, opened it, found heroin, and then reattached the tank without damaging the car.

Nina moves to suppress, arguing that removing the fuel tank was too intrusive to be conducted without reasonable suspicion. How should the court rule?

Explanation. The majority held that suspicionless border-search authority over vehicles includes removing, disassembling, and reassembling a fuel tank. The Court rejected importing a routine-versus-nonroutine balancing test from personal-search cases into vehicle border searches. Because the search occurred at the international border and was not shown to be destructive, reasonable suspicion was not required.