He made this announcement on Friday, Dec 18th 2016, while speaking to an inner circle of his group, telling them that he killed Tasiu because he and another Boko Haram senior commander, Baba Ammar, plotted to oust him.
He also accused them of sending troops out on raids without his knowledge and spreading rumours among his lieutenants that he intended to kill them.
In a 50 minute video, shot last year but recently brought to the knowledge of the public, Shekau while having a meeting with some of his members, blasted those grumbling about the killing of Tasiu and took credit for his death.
“I killed Tasiu,” he said. “You should hear me: I killed Tasiu, hear me well.” Vanguard quoted Shekau.
He went on to explain his reason for doing so, revealing that death was the punishment for any follower who plots against the leader of a group.
“Tell me, what is the punishment for people that plot against their leader?” Shekau asked in the video.
“By our code of allegiance we don’t hesitate to pass appropriate sanction on any one of us that commits an offence.”