Attorney General Eric Holder on Tuesday struggled to explain contradictory testimony about when he knew about Operation “Fast and Furious,” the program under which the Obama administration let guns “walk” into the hands of Mexican drug lords, only to see the weapons turn up at crime scenes, including at the murder of a U.S. border patrol agent.

Asked during May testimony before the House Oversight and Government Reform Committee when he first heard about the program, Holder said, “I’m not sure of the exact date, but I probably heard about Fast and Furious for the first time over the last few weeks.”