The leader of Boko Haram, Imam Abubakar Shekau, has reportedly challenged the authority of Nigeria’s president in an online video, promising more attacks. Shekau is believed to be the successor to Yusuf Mohammed, the founder of the group, who was allegedly killed by the police in 2009 after he was captured alive in the uprising that led to hundreds of deaths. Boko Haram has claimed responsibility for the majority of the assassinations and bombings carried out in recent times in the country. Boko Haram, whose name in Hausa means “Western education is sin”, has carried out attacks in North-east and Abuja that killed at least 510 people last year alone. The sect has been blamed by the government for killing at least 67 people in the last weeks alone, continuing its campaign to Islamise Nigeria. Yesterday, suspected Boko Haram gunmen attacked a bus in Yobe State carrying Igbo traders fleeing the North, killing four people, police said. Shekau took control of the sect after a riot and security crackdown in July 2009 which saw Boko Haram’s leader and about 700 others killed.