High Quality Content by WIKIPEDIA articles! Hans Köchler's Lockerbie trial observer mission stemmed from the dispute between the United Kingdom, the United States, and Libya concerning arrangements for the trial of two Libyans accused of causing the explosion of Pan Am Flight 103 over Lockerbie on 21 December 1988. The dispute was resolved on the basis of legally-binding United Nations Security Council resolution 1192 of 27 August 1998. N Security Council resolution 1192 "welcomed" "the initiative for the trial of the two persons charged with the bombing of Pan Am flight 103 ... before a Scottish court sitting in the Netherlands" and "invited" the Secretary-General of the United Nations "to nominate international observers to attend the trial". By a letter dated 28 October 1997, the Permanent Representative of the United Kingdom had informed the Secretary-General "that the United Kingdom would welcome the presence of international observers from the United Nations at the trial ofthe suspects in the Lockerbie bombing".