Trump's new tariffs warning sends stocks plunging; Tariffs on Mexico would hit U.S. consumers hard; White House "Enthusiastic" about Attorney General Barr's interview defending Trump's attacks on government institutions; Justice Department fails to release transcripts of Flynn calls with Russian ambassador; Multiple injuries after shooting incident in Virginia Beach; Thousands threatened by historic flooding, levy breaches; U.S. checking reports that North Korea executed senior official involved in failed summit with Trump via Knit