You may have never heard of Kim Yong-chol. But you’ve probably seen him before. Here he is sitting next to Ivanka Trump at the Winter Olympics in Pyeongchang. Here, with the North Korean leader at the inter-Korean summit in April. Here, leading a delegation to South Korea during military talks in 2007. Here, with Kim Jong-il. And here, with Secretary of State Mike Pompeo in Pyongyang in May. The former head of North Korea’s spy agency is said to be one of Kim Jong-un’s closest aides. He worked for all three leaders of the Kim dynasty, and is one of its longest- serving senior officials. But he has a controversial past. He’s still on sanctions lists in South Korea and the United States. South Korea accuses Kim Yong-chol of being involved in several high-profile attacks. He was allegedly behind the sinking of a South Korean naval ship in 2010 that killed 46 sailors, and of masterminding an attack on a South Korean island the same year. Under his leadership, North Korea’s spy agency was suspected by the U.S. of launching a cyberattack against Sony Pictures in 2014. It apparently was in retaliation to the film “The Interview,” which mocked Kim Jong-un. “I don’t need my father.” Kim Yong-chol is also no stranger to nuclear diplomacy. He’s been involved in various rounds of negotiations to limit North Korea’s nuclear weapons. This week, he became the highest-ranking North Korean official to visit the United States since 2000.