Nigeria, Oct. 21 -- Over the past three months, security forces from the Lake Chad Basin countries - Nigeria, Niger, Chad, and Cameroon - have announced the arrest or killing of key figures in Boko Haram factions. Although these gains will weaken the terrorist groups, they have shown an ability to outlast their leaders and reinvent themselves. Security forces must therefore remain vigilant and proactive.

In August, Chadian police announced the arrest in the capital N'Djamena of Muslim Yusuf, son of Boko Haram founder Mohammed Yusuf. Muslim's older brother Habib Yusuf, also known as Abu Musab al-Barnawi, is the current leader of the Boko Haram faction Islamic State West Africa Province (ISWAP).

In the same month, the Nigerian Army announ...