They just both ran investigations of themselves which cleared them completely at taxpayer expense:

With his office suddenly engulfed in scandal over lane closings at the George Washington Bridge, Gov. Chris Christie of New Jersey two months ago summoned a pair of top defense lawyers from an elite law firm to the State House and asked them to undertake an extensive review of what had gone wrong.

Now, after 70 interviews and at least $1 million in legal fees to be paid by state taxpayers, that review is set to be released, and according to people with firsthand knowledge of the inquiry, it has uncovered no evidence that the governor was involved in the plotting or directing of the lane closings.

The review is the first of multiple inquiries into a scandal that has jeopardized Mr. Christie’s political future. It will be viewed with intense skepticism, not only because it was commissioned by the governor but also because the firm conducting it, Gibson Dunn & Crutcher, has close ties to the Christie administration and the firm’s lawyers were unable to interview three principal players in the shutdowns, including Bridget Anne Kelly, the governor’s former deputy chief of staff.

But lawyers from the team who led the inquiry are prepared to vigorously defend their work, which they described as an unfettered look into the inner workings of an administration known to prize loyalty and privacy.

This is perhaps the only internal investigation with less credibility than the FBI, today, at least.