 Everyone hear me clearly and listen to me at home and make no mistake. The House is conducting an immediate and thorough investigation of these tragic events. The first congressional hearing is scheduled for Monday next week. Secret Service Director Kim Cheadle is set to testify before the House Oversight Committee. Trial Snyder, NPR News. Meanwhile, investigators are still trying to figure out a motive for Saturday's shooting of Donald Trump. NPR's Quill Lawrence reports from Bethel Park, Pennsylvania.