Njenga is a minor antagonist in Crocodile Tears who works for Desmond McCain.
Njenga is the leader of the Kikuyu tribesmen who serve as bodyguards for McCain in Kenya, and when Alex Rider is smuggled into the country by Myra Bennett, Njenga guards Alex overnight so that he can be tortured the next day. Njenga is a cold and ruthless killer, and according to Bennett, he has no problem with inflicting pain on a child. He even shoots a monkey which is making too much noise in a tree, just to advertise his lack of emotion. When Alex is making his way to Simba Dam to stop McCain's plans, Njenga leads the hunt for him. He tries to kill Alex on top of the dam but never gets the chance, as Alex had placed a bomb there which explodes and destroys the dam. The force also causes Njenga to lose his balance and fall to his death, while the other Kikuyu tribesmen are washed away in the flood.