The cause of death of Dag Hammaskjold, former Secretery General of the UN.

LONDON — It has been one of Africa’s enduring mysteries, redolent of days when mercenaries roamed the bushlands and outsiders scrambled to exploit a continent’s riches: How and why did Dag Hammarskjold, the United Nations secretary general, die? The DC-6 airplane carrying Mr. Hammarskjold, a Swed...

http://www.nytimes.com/2014/12/17/world/africa/dag-hammarskjold-death-inquiry.html

PS

A similar death occurred to Patrice Lumumba.