The murderer, Nfor Etienne Ngwana, had hidden in the attic and waited until Mr Nicholas left for work before attacking Dr Warren. Police arrested some of the gang who said Collins had offered them cash to kill Dr Warren. Mr Nicholas, who is also a gorilla expert who had been working with Dr Warren on the Takamanda-Mone Landscape Project studying Cross River gorillas, said: “The only person with a grudge I could think about was this person Collins who we had let go. He had a relationship with this volunteer who was a volatile character. The fact that he lost his chance of a visa and his ticket to have a life overseas and have a life outside Cameroon, may be why.”