General Motors CEO Mary Barra walks past former US Attorney Anton Valukas, investigator , Jenner & Block, left, and television cameras as she arrives on Capitol Hill in Washington, Wednesday, June 18, 2014, to testify before the House Oversight and Investigations subcommittee hearing examining the facts and circumstances that contributed to General Motors’ failure to identify a safety defect in certain ignition switches and initiate a recall in a timely manner.