Officers referred the 35-year-old woman and her three children for an additional search of a Nissan hatchback as they attempted to enter the U.S. on Friday at Arizona's San Luis Port of Entry.
A CBP canine alert to the 12-year-old led officers to discover more than two pounds of cocaine, worth almost $24,000, wrapped around her torso.
Border Patrol officers seized their vehicle, as well as the drugs.
The case was turned over to U.S. Immigration and Customs Enforcement's Homeland Security Investigations.