“So far, the information we have is that they were working jointly [with Chihuahua authorities]. … So the whole investigation has to be done by the Federal Attorney General’s Office [FGR] to see if the constitution or the National Security Law was violated,” Sheinbaum said. Two Chihuahua security officials, including the director of the State Investigation Agency, were also killed when a vehicle in which they and the U.S. officials were traveling plunged into a ravine early Sunday. On Monday, Sheinbaum said that her administration was asking the Chihuahua government and U.S. authorities for information about their security collaboration in the northern border state.

She said her government was unaware of the collaboration. The president is steadfastly opposed to the participation of U.S. officials in security operations in Mexico, although her government and the Trump administration do cooperate on security issues and share intelligence. She has declined offers from U.S.

President Donald Trump to send the U.S. Army into Mexico to combat cartels. Citing two unnamed sources, The Washington Post reported on Tuesday that the deceased U.S. officials “worked for the Central Intelligence Agency [CIA] as part of a significantly expanded role in battling narcotics trafficking in the Western Hemisphere.” The Post noted that “Chihuahua’s attorney general, César Jáuregui Moreno, told Mexico’s El Universal newspaper that the Americans did not directly participate in the Mexican raid” on a “clandestine drug lab in a remote area” of Chihuahua.

“Jáuregui, the attorney general in Chihuahua, said Sheinbaum’s office was not notified because only Mexican agents — about 40 in all — participated in the seizure of the drug lab, which took about three months to plan,” the Post reported. Jáuregui “said the Americans, whose agency affiliation he did not identify, were doing training work ‘about eight to nine hours away’ from the location of the operation against the drug lab. After that operation, they met with personnel from Chihuahua’s state investigation agency, known as AEI, which participated in the raid,” the Post wrote.

The New York Times also reported that the U.S. officials killed on Sunday were CIA officers. The Times reported that “Mexico’s national security law forbids foreign agents, including U.S. military and law enforcement officials, from operating in the country without authorization from the government.” “American officials working directly with state-level authorities without federal approval would be a breach of the Constitution,” the newspaper wrote. Sheinbaum: Mexico will send protest note to US if investigation confirms joint operation with Chihuahua On Tuesday morning, Sheinbaum highlighted that a Mexican state is not legally permitted to “directly” enter into a security agreement with a U.S. government agency.

Such an agreement has to be authorized by the federal government, she stressed. 🔴“Sí estaban trabajando conjuntamente”, dice la presidenta Claudia Sheinbaum sobre los agentes de Estados Unidos en Chihuahua tras el cambio de declaración del fiscal estatal, César Jáuregui. Añade que debe investigarse si se violó la Constitución y que las autoridades… pic.twitter.com/8ghSqQEWGB — Azucena Uresti (@azucenau) April 21, 2026 Sheinbaum also emphasized that joint security operations with the United States are not allowed within Mexican territory. She said that if the FGR investigation confirms there was a joint operation between the United States and Chihuahua, Mexico would send a protest note to the U.S. government and request that such collaboration cease.

“Any activity that U.S. agencies carry out in our territory has to adhere to the National Security Law,” she said. Sheinbaum also said that if an investigation finds that the state of Chihuahua and the CIA were carrying out a joint security operation without federal approval, her government would seek “explanations” from the U.S. Embassy in Mexico and the government of Chihuahua, which is currently governed by the opposition National Action Party.

She said that she spoke to U.S. Ambassador to Mexico Ron Johnson on Monday, but their conversation focused on conveying condolences to each other over the deaths of the U.S. and Mexican security officials in Sunda