CEDAR FALLS, Iowa (AP) - First lady Michelle Obama said Saturday that the U.S. military specialists who killed terrorist leader Osama bin Laden showed "the very essence" of public service. Mrs. Obama made her first public remarks about bin Laden's death during the commencement address at University of Northern Iowa. U.S. officials have said Navy SEALs shot and killed bin Laden and four others Monday at his luxury compound in Abbottabad, Pakistan.