American girl, 7, killed during Mexican cartel operation as police face investigation

A 7-year-old dual U.S.-Mexican citizen was shot and killed during a security operation in Matamoros, Mexico. Her mother says police aboard a helicopter opened fire on the family's vehicle. 

A 7-year-old dual U.S.-Mexican citizen was shot and killed during a security operation in Matamoros, Mexico. Her mother says police aboard a helicopter opened fire on the family's vehicle. Three officers are under investigation, according to reports.