Hutu Rwanda, this led to the "Social revolution" and Hutu violence against Tutsis. Tens of thousands of Tutsis were killed and many others fled to neighboring countries, such as Burundi, Uganda and expanding the Banyamulenge Tutsi ethnic group in the South Kivu region of the Belgian Congo. Later, exiled Tutsis from Burundi invaded Rwanda, prompting Rwanda to close its border with Burundi. In Burundi, a campaign of genocide was conducted against Hutu population in 1972, and an estimated 100,000 Hutus died. In 1993, Burundi's first democratically elected president, Melchior Ndadaye, who was Hutu, was believed to be assassinated by Tutsi officers,
Rwandan genocide between Hutu, Tutsi, and Twa. The systematic destruction of the judicial system during the genocide and civil war was a major problem. After the genocide, over one million people were potentially culpable for a role in the genocide, nearly one-fifth of the population remaining after the summer of 1994. After the genocide, the RPF pursued a policy of mass arrests for the genocide, jailing over 100,000 in the two years after the genocide. The pace of arrests overwhelmed the physical capacity of the Rwandan prison system, leading to what Amnesty International deemed "cruel, inhuman, or degrading treatment". The country's nineteen