Packets of Class A substances are being put under tourists' cars using magnets
Drug smugglers are turning "trusted travellers" into unwitting mules by placing containers with powerful magnets under their cars in Mexico and then recovering the illegal cargo far from the view of border authorities in the United States.
One motorist spotted the containers while filling up with petrol after crossing into southern California this month, and thought it might be a bomb.
His call to police prompted an emergency response, and then a shocker - 13 pounds of heroin were packed inside.
There have been four such incidents in San Diego since January 12, all involving drivers enrolled in the "trusted traveller" programme, which enables hundreds of thousands of people who pass extensive background checks to whizz past inspectors with less scrutiny.
