Before the Rwanda massacre, Tutsis were 10% and Hutus 90%. The Tutsis mostly lived in the North and Hutus south. Tutsis have, along with Somalis and Etheopeans been classified Caucasian due to nose/skull shape. Hutus are Bantu negroes.
Tutsis = ruling class and control business, banks,military. Hutus resented them - a class and racial divide. Simmering resentmentof the lower orders eventually boiled over and the Hutus organised themselves to kill Tutsis.
The criteria = skinny, tall, thin nosed, rich or long fingers (chop with machete) even Hutus who looked like that got killed.
A great many Tutsis were massacred but organised to fight back and regained control of Rwanda despite being well outnumbered, and drove the Hutu militia out into Congo.
They forgave the Hutus and all returned to previous situation of Tutsis ruling Rwanda.
This suggest cognitive differences between Tutsis and Hutus which seem not to be racially identical. Tutsis were able to do strategy and military planning and had the noble spirit to forgive. They regard the Hutus as being lethargic, dangerous and violent and resentful. Hutus see Tutsis as clever and scheming.
Over a million people died in the race war. Tutsis targetted the armed gangs, but Hutus targetted anyone resembling a Tutsi. All "prejudice" if that is really the appropriate term, was from the Hutus towards the Tutsis, who were only reacting in defence.