Two U.S. officials killed in a vehicle crash as they returned from destroying a clandestine drug lab in northern Mexico over the weekend were working for the CIA. That's according to a U.S. official and two other people familiar with the matter who spoke on the condition of anonymity Tuesday. The crash also killed two Mexican investigators. Mexican authorities say the group was returning from an operation to destroy the drug labs of criminal groups. The crash has sparked debate over U.S. involvement in Mexican security operations. Mexican President Claudia Sheinbaum faces pressure from U.S. President Donald Trump's administration to crack down on cartels. The CIA and State Department have declined to comment.