The Center for Public Integrity

A group of House Republicans are demanding the details of a federal investigation that enabled guns suspected of being bought by a drug cartel to slip into Mexico.

Homeland Security secretary Janet Napolitano told a Senate committee today that she knew nothing of a shift in strategy that delayed arrests of suspected gun traffickers and allowed hundreds of guns to be transported into Mexico.

Sen. Charles Grassley, the top Republican on the Senate Judiciary Committee, demanded Tuesday that an independent watchdog be used to investigate the Bureau of Alcohol, Tobacco, Firearms and Explosives decision to let hundreds of guns fall into the hands of straw buyers for suspected Mexican weapons traffickers in hopes of making a bigger criminal case.

Mexico's foreign ministry is demanding information from the U.S. government on a controversial Bureau of Alcohol, Tobacco, Firearms and Explosives operation that let more than 1,700 weapons pass through straw buyers for suspected Mexican gun runners in hopes of making a bigger criminal case.

The head of the Bureau of Alcohol, Tobacco, Firearms and Explosive on Thursday night ordered an outside evaluation of his agency's efforts to combat Mexican gun trafficking following a Center for Public Integrity report that ATF supervisors allowed more than 1,700 guns to flow to straw buyers with the expectation the weapons might cross the border and even be used in crimes.