(FILES) This file photo taken on February 19, 2019 shows a man believed to be North Korean negotiator Kim Hyok Chol (centre L-blue tie) after arriving on an Air Koryo flight from Pyongyang, at Beijing international airport. - North Korea executed its special envoy to the United States, Kim Hyok Chol, following the collapse of the second summit between leader Kim Jong Un and President Donald Trump, a South Korean newspaper reported on May 31, 2019. (Photo by Ed JONES / AFP)