GM...confirmed...that the engineers were placed on leave following...an independent investigation into a recall of 2.6 million cars with ignition defects…GM has traced a defect in an ignition switch to at least 13 deaths...GM...knew of the problem as early as 2004, and now federal investigators…are asking why the company didn't issue a recall years ago...[Ray] DeGiorgio was the engineer who in 2006 approved a part modification to fix the issue...The part number, however, was not changed...As a result, the change flew under the radar for several years. Lawmakers...accused DeGiorgio of lying and attempting to cover up the issue...GM declined to make the engineers available for comment...[T]he National Highway Traffic Safety Administration is fining GM $7,000 a day for failing to answer 107 questions about its ignition switch recall by the regulator's April 3 deadline…