What led to the Rwanda genocide?

Under colonial rule,tensions had long simmered between ethnic Hutus, predominantly farmers, and Tutsis, who raised cattle.Hutus were in the majority, though Tutsis generally commanded greater wealth and social position.

A Hutu uprising in 1959 resulted in a civil war that ended Tutsi domination.
In 1962, when Rwanda gained independence from Belgium, 120,000 Rwandans — mostly Tutsis — fled the country. Hutu leaders gained control of Rwanda.
Starting in the late 1980s, Rwanda exile groups made political and military moves to repatriate.
Peacemaking attempts in 1993 by the United Nations and regional African governments were unsuccessful.
On April 6, 1994, Rwanda President Juvenal Habyarimana and Burundi President Cyprien Ntaryamira, both Hutus, were killed in a rocket attack on their airplane, while returning from peace negotiations.
A 100-day spree of brutal violence immediately ensued, perpetrated mainly by Hutus against Tutsis and moderate Hutus.