The Federal Bureau of Investigation (part of the US Justice Department headed by Obama crony Attorney General Eric Holder) found no criminal wrongdoing on the part of the Obama Administration in their probe of the IRS, which Congressional testimony clearly held, targeted Obama's political enemies. Really.
The FBI has been used as a cat's paw by the Obama Administration for a number of politically motivated "protection measures" designed to limit the government's exposure. Remember the FBI visit to the US Consulate in Benghazi where CNN found Ambassador Chris Steven's diary after they left following their search for evidence?
Attorney General Holder still stands accused of lying to Congress and true to his and the President's Chicago roots, he remains in Obama's good graces, well within the 'circle of trust'.
Can the FBI regain their credibility? Yes - but not while Barack Obama is in office.