During a relative thaw in relations between Pyongyang and Washington in the early 1990s, North Korea returned 208 boxes of human remains, followed by a further batch in 2000. The remains were transferred to the Department of Defense's POW/MIA Accounting Agency, based in Hawaii, where experts set about the long and painstaking process of identifying the individual servicemen. In all, the agency found bones from more than 600 US personnel.