GM engineer Ray DeGiorgio did not say anything to the congressional investigators to suggest that Chief Executive Mary Barra knew about the defective switch before she took the top job at the company this year, the Times said, quoting people familiar with the session. DeGiorgio, who was suspended by GM on April 10, designed the switch for the 2003 Saturn Ion and other models, including the Chevrolet Cobalt, which have been recalled.