BRIEF-U.S. drops criminal case against ex-JPMorgan traders in 'London Whale' case

July 21 (Reuters) - U.S. SAYS NO LONGER BELIEVES IT CAN RELY ON TESTIMONY OF BRUNO IKSIL, A FORMER JPMORGAN COLLEAGUE, IN PROSECUTING MARTIN-ARTAJO AND GROUT U.S. DECIDES TO DROP CRIMINAL CHARGES AGAINST FORMER JPMORGAN TRADERS JAVIER MARTIN-ARTAJO, JULIEN GROUT IN 'LONDON WHALE' CASE -- COURT FILING U.S. SAYS DEFENDANTS LIVE OUTSIDE THE COUNTRY AND HAVE REFUSED TO DEFEND THEMSELVES IN NEW YORK, AND EFFORTS TO EXTRADITE THEM HAVE BEEN UNSUCCESSFUL OR DEEMED FUTILE