(CBS News)

WASHINGTON – Federal agent John Dodson says what he was asked to do was beyond belief.

He was intentionally letting guns go to Mexico?

“Yes ma’am,” Dodson told CBS News. “The agency was.”

An Alcohol, Tobacco and Firearms senior agent assigned to the Phoenix office in 2010, Dodson’s job is to stop gun trafficking across the border. Instead, he says he was ordered to sit by and watch it happen.

Investigators call the tactic letting guns “walk.” In this case, walking into the hands of criminals who would use them in Mexico and the United States.

Documents show the inevitable result: The guns that ATF let go began showing up at crime scenes in Mexico. And as ATF stood by watching thousands of weapons hit the streets… the Fast and Furious group supervisor noted the escalating Mexican violence.

One e-mail noted, “958 killed in March 2010 … most violent month since 2005.” The same e-mail notes: “Our subjects purchased 359 firearms during March alone,” including “numerous Barrett .50 caliber rifles.”

Dodson feels that ATF was partly to blame for the escalating violence in Mexico and on the border. “I even asked them if they could see the correlation between the two,” he said. “The more our guys buy, the more violence we’re having down there.”

Video here: