Federal agent John Dodson says what he was asked to do was beyond belief. He was intentionally letting guns go to Mexico. An Alcohol, Tobacco and Firearms [ATF] 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. Dodson's bosses say that never happened. Agent Dodson and other sources say the gun walking strategy was approved all the way up to the Justice Department. The idea was to see where the guns ended up, build a big case and take down a cartel. And it was all kept secret from Mexico. ATF named the case "Fast and Furious." 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." Dodson feels that ATF was partly to blame for the escalating violence. Senior agents including Dodson ... confronted their supervisors over and over. Their answer ... "If you're going to make an omelette, you've got to break some eggs." On Dec. 14, 2010, Border Patrol Agent Brian Terry was gunned down. Two assault rifles ATF had let go nearly a year before were found at Terry's murder. Dodson said, "I felt guilty. I mean it's crushing." Dodson said they never did take down a drug cartel. However, he said thousands of Fast and Furious weapons are still out there and will be claiming victims on both sides of the border for years to come.