John Hanning Speke (4 May 1827 - 15 September 1864) was an English explorer and officer in the British Indian Army who made three exploratory expeditions to Africa. He is most associated with the search for the source of the Nile and was the first European to reach Lake Victoria (known to locals as Nam Lolwe in Dholuo and Nnalubaale or Ukerewe in Luganda). Speke is also known for propounding the Hamitic hypothesis in 1863, in which he supposed that the Tutsi ethnic group were descendants of the biblical figure Ham, and had lighter skin and more Hamitic features than the Bantu Hutu over whom they ruled. The racial hypothesis he proposed contributed to the conditions for the 1994 Rwandan genocide, in which 500,000 to 600,000 Tutsi were slaughtered.