A group of congressional leaders is calling for an investigation into reports that US government officials are ‘tipping off’ the Mexican government about civilian patrol groups like the Minutemen.

Twenty-one congressional leaders have called for an independent investigation into reports that officials from the Department of Homeland Security and U.S. Customs and Border Protection were providing information to the Mexican government about civilian patrol groups.

The lawmakers are asking the Government Accountability Office, a nonpartisan investigative arm of Congress, to look into the relationship between Homeland Security and the Mexican Foreign Consulate.

In a letter sent Monday to David M. Walker, comptroller general of the United States, the congressional leaders expressed concern that the Mexican Foreign Ministry is unduly influencing the federal law enforcement agency.

“Additionally, with reports that our Border Patrol officials are identifying Minutemen locations and compromising their security by communicating these with the Mexican Foreign Ministry officials, we would also like you to identify the extent of the relationship between the Department of Homeland Security and the Mexican Foreign Ministry,” the letter stated.

The call for an independent investigation came on the heels of a letter sent last week by California Reps. Duncan Hunter, R-El Cajon, and Darryl Issa, R-Vista, along with Rep. John Culberson, R-Texas, asking Homeland Security Secretary Michael Chertoff for a full investigation into all circumstances and events related to civilian border observation groups and the Mexican government.