Abubakar Shekau, of the radical Nigerian Islamic sect Boko Haram — the man who has claimed responsibility for abducting schoolgirls in the town of Chibok — is, in a loose sense, a leader of a guerrilla group with limited hierarchy and several factions.

Western media have taken to calling him "shadowy," but he is the only recognizable face of Boko Haram outside northern Nigeria and expands on his infamy by releasing videos in English in which he talks of his murderous intent.

He is the man who cheated death — the authorities have claimed several times that he has been killed — and he has been injured by Nigerian forces, shot in the thigh in 2009 and shot again in 2012 when he tried to attend a ceremony to mark the birth of his baby.