Shekau was “believed to be fatally wounded” during an air strike on the Sambisa forest in the northeastern state of Borno on Aug. 19, army spokesman Sani Usman said in an e-mailed statement Tuesday.
The announcement was made as U.S. Secretary of State John Kerry is visiting Nigeria to discuss security issues, including Boko Haram. The Nigerian authorities have reported Shekau’s probable death at least twice before, including in 2014 and 2013.
Shekau took over the militant group in 2009, when it began an insurgency that’s killed tens of thousands of people in a bid to impose its version of Islamic law on Africa’s most populous nation. While Islamic State announced this month that Abu Musab al-Barnawi was Boko Haram’s new leader, Shekau said in a video released on Aug. 8 that he was still in charge.