A letter recovered in Osama bin Laden’s compound reveals that Boko Haram’s leader, Abubakar Shekau, sought direct contact with al Qaeda’s deputy leader at the time. There is abundant evidence that Boko Haram was supported by al Qaeda’s international network until Shekau swore allegiance to the Islamic State’s Abu Bakr al Baghdadi in 2015.

The claim of responsibility for last month’s suicide attacks in Chad comes after the jihadist group killed more than 200 people in Nigeria last week.
