Rep. Darrell Issa discusses Attorney General Eric Holder's testimony and the investigation into the Justice Department's "Operation Fast and Furious". An operation which deliberately let operatives of Mexican drug cartels purchase guns at licensed U.S. firearms dealers and did nothing to intercept the gun purchaser or retrieve the guns even when they were under active surveillance by federal law enforcement officials.
Much more detail at CNS News including this key bit:
Before the operation was ended, however, Border Patrol Agent Brian Terry was murdered by alleged drug cartel operatives in Arizona. Among the 20 individuals indicted as result of Operation Fast and Furious was Jaime Avila. As early as November 2009, federal authorities had had evidence of illegal gun purchases by Avila. Two AK-47s purchased by Avila—with the full knowledge of the ATF in the conduct of Operation Fast and Furious--were found at the scene of Agent Terry’s murder.