New evidence has emerged in one of the most enduring mysteries of United Nations and African history, suggesting that the plane carrying the UN secretary general Dag Hammarskjld was shot down over Northern Rhodesia (now Zambia) 50 years ago, and the murder was covered up by British colonial authorities. A British-run commission of inquiry blamed the crash in 1961 on pilot error and a later UN investigation largely rubber-stamped its findings. They ignored or downplayed witness testimony of villagers near the crash site which suggested foul play. The key witnesses were located and interviewed over the past three years by Gran Bjrkdahl, a Swedish aid worker based in Africa. The investigation led Bjrkdahl to previously unpublished telegrams ... which illustrate US and British anger at an abortive UN military operation that the secretary general ordered on behalf of the Congolese government against a rebellion backed by western mining companies and mercenaries in the mineral-rich Katanga region. Hammarskjld was flying to Ndola for peace talks with the Katanga leadership at a meeting that the British helped arrange. The fiercely independent Swedish diplomat had, by then, enraged almost all the major powers on the security council with his support for decolonisation, but support from developing countries meant his re-election as secretary general would have been virtually guaranteed at the general assembly vote due the following year.