How Mexican killers got US guns from 'Fast and Furious' operation

US officials thought they would catch Mexican criminals in a bold gun-running sting called 'Fast and Furious.' Instead, they inadvertently armed drug cartels as the operation spiraled out of control, a congressional report finds. ... According to whistleblowers and key witnesses, however, the real lesson behind Fast and Furious, a two-year operation that ended in January 2011, is how "groupthink" clouded decision-making at the highest levels of government, causing an agency to go against its basic instincts — which is to not allow arms to be trafficked illegally — and consequently contribute, not detract, from border violence. "These guns weren't going for a positive cause, they were going for a negative cause," ATF attaché Carlos Canino told the congressional oversight committee. "The ATF armed the [Sinaloa] cartel. It's disgusting."