

An alternative theory is that the migration was slow and steady from neighbouring regions, with incoming groups bearing high genetic similarity to the established ones, and integrating into rather than conquering the existing society. Historians have several theories regarding the nature of the Bantu migrations: one theory is that the first settlers were Hutu, while the Tutsi migrated later and formed a distinct racial group, possibly of Cushitic origin. Between 700 BC and 1500 AD, a number of Bantu groups migrated into Rwanda, and began to clear forest land for agriculture. The earliest inhabitants of what is now Rwanda were the Twa, a group of aboriginal pygmy hunter-gatherers who settled in the area between 8000 BC and 3000 BC and remain in Rwanda today.

4.1 Killings by the Rwandan Patriotic Front.4 Rwandan Patriotic Front's military campaign and victory.1.2 Revolution and Hutu–Tutsi relations after independence.1.1 Pre-independent Rwanda and the origins of Hutu, Tutsi and Twa groups.

Although the Constitution of Rwanda claims that more than 1 million people perished in the genocide, the real number killed is substantially lower. Today, Rwanda has two public holidays to mourn the genocide, and " genocide ideology" and "divisionism" are criminal offences. In 1996, the RPF-led Rwandan government launched an offensive into Zaire (now the Democratic Republic of the Congo), home to exiled leaders of the former Rwandan government and many Hutu refugees, starting the First Congo War and killing an estimated 200,000 people. The genocide had lasting and profound effects. The RPF quickly resumed the civil war once the genocide started and captured all government territory, ending the genocide and forcing the government and génocidaires into Zaire. Sexual violence was rife, with an estimated 250,000 to 500,000 women raped during the genocide. The militia murdered victims with machetes and rifles. Hutu gangs searched out victims hiding in churches and school buildings. Most of the victims were killed in their own villages or towns, many by their neighbors and fellow villagers. The scale and brutality of the genocide caused shock worldwide, but no country intervened to forcefully stop the killings. Genocidal killings began the following day when majority Hutu soldiers, police, and militia executed key Tutsi and moderate Hutu military and political leaders. While many historians argue that genocide against the Tutsi had been planned for a few years, the catalyst became Habyarimana's assassination on 6 April 1994, creating a power vacuum and ending peace accords. In an effort to bring the war to a peaceful end, the Rwandan government led by Hutu president, Juvénal Habyarimana signed the Arusha Accords with the RPF on 4 August 1993. Over the course of the next three years, neither side was able to gain a decisive advantage. In 1990, the Rwandan Patriotic Front (RPF), a rebel group composed mostly of Tutsi refugees, invaded northern Rwanda from their base in Uganda, initiating the Rwandan Civil War.

The most widely accepted scholarly estimates are around 500,000 to 662,000 Tutsi deaths. During this period of around 100 days, members of the Tutsi minority ethnic group, as well as some moderate Hutu and Twa, were killed by armed militias. The Rwandan genocide, also known as the genocide against the Tutsi, occurred between 7 April and 15 July 1994 during the Rwandan Civil War.
