From Wikipedia

Ghosts Of Rwanda

The Rwandan Genocide was the 1994 mass killing of hundreds of thousands of Rwanda's Tutsis and Hutu political moderates by the Hutu dominated government under the Hutu Power ideology. Over the course of approximately 100 days, from the assassination of Juvénal Habyarimana on 6 April through mid-July, at least 500,000 people were killed. Estimates of the death toll have ranged between 500,000 and 1,000,000, or as much as 20% of the total population of the country.

In 1990 the Rwandan Patriotic Front (RPF), a rebel group, composed mostly of Tutsi refugees, invaded northern Rwanda from Uganda. The Rwandan Civil War, fought between the Hutu regime, with support from Francophone nations of Africa and France itself, and the RPF, with support from Uganda, vastly increased the ethnic tensions in the country and led to the rise of Hutu Power, an ideology that asserted that the Tutsi intended to enslave Hutus and thus must be resisted at all costs. Despite continuing ethnic strife, including the displacement of large numbers of Hutu in the north by the rebels and periodic localized extermination of Tutsi to the south, pressure on the government of Juvénal Habyarimana resulted in a cease-fire in 1993 and the preliminary implementation of the Arusha Accords.

The assassination of Habyarimana in April 1994 was the proximate cause of the mass killings of Tutsis and pro-peace Hutus. They were carried out primarily by two Hutu militias associated with political parties: the Interahamwe and the Impuzamugambi. The genocide was directed by a Hutu power group known as the Akazu. The killing also marked the end of the peace agreement meant to end the war and the Tutsi RPF restarted their offensive, eventually defeating the army and seizing control of the country.