It's his father (Kimnyole) who prophesied coming of the colonialists, not koitalel. Kinyole was stoned by his own people in the late 1800s when he failed to `prophesy` the outbreak some cattle disease (rinderpest I think) that killed almost all their cattle. His son Koitalel was shot at point blank range by the british in 1908 when he agreed to meet them for a truce; Koitale's son (I forgot his name) ended up in jail and is the longest serving political prisoner in Kenya's history.
His skull is in a brittish museum. Only a fool would keep the skull of a man who was able to disable their guns. They need to send it all back. In this season, they need to send his skull back.