The former Port Authority official who personally oversaw the lane closings on the George Washington Bridge in the scandal now swirling around Gov. Chris Christie of New Jersey said on Friday that the governor knew about the lane closings when they were happening, and that he had the evidence to prove it. In a letter released by his lawyer, the official, David Wildstein, a high school friend of Mr. Christie’s who was appointed with the governor’s blessing at the Port Authority of New York and New Jersey, which controls the bridge, described the order to close the lanes as “the...