DAKAR, Senegal — The head of Nigeria’s best-known terrorist group, Boko Haram, has been reported dead many times before.
But now evidence that this time he might really be dead has emerged via an audio message, apparently recorded by the head of a rival extremist group.
In it, the leader of Islamic State West Africa Province, known as ISWAP, appeared to confirm that Abubakar Shekau, Boko Haram’s violent and erratic leader, killed himself rather than be taken prisoner in May.
“Shekau preferred to be humiliated in the hereafter than on earth,” the voice in the recording says. “He killed himself instantly by detonating an explosive.”
Mr. Shekau was best known for the kidnapping of hundreds of schoolgirls from a boarding school in Chibok in 2014. But his fighters kidnapped, killed, raped and robbed many thousands more, and sent untold numbers of Nigerians to their deaths as suicide bombers. Millions have been displaced in the region as a result of the violence.
The death of Mr. Shekau, if true, marks the end of a brutal era for northeast Nigeria and its neighboring countries in the Lake Chad region.
But it could also signify the beginning of a new era, in which ISWAP takes new territory after getting rid of its chief rival, and amps up confrontations with the Nigerian state and its military. ISWAP splintered from Boko Haram, reportedly in part because of Mr. Shekau’s violence against Muslim civilians.
ISWAP has lately posed the greater threat to the Nigerian military, which is stretched as it is deployed to fight various crises in almost every one of the West African country’s states. ISWAP has pledged allegiance to ISIS, the Islamic State in Iraq and Syria.
In late May, reports trickled out that heavily armed ISWAP members had arrived at Mr. Shekau’s hide-out in the Sambisa forest. When he realized that there was no way to escape, he detonated a suicide vest he was wearing, the reports said.
The Nigerian military, which has largely retreated to garrison towns in the northeast rather than trying to control the countryside, said it was investigating. It is extremely difficult to confirm Mr. Shekau’s death definitively, and he has been falsely reported as dead before — by some counts, eight times.
The audio was shared with investigative journalist Ahmad Salkida, who is known to have a good knowledge of Boko Haram and ISWAP activity, and who published an article about it on Humangle, the news site he co-founded. The voice sounds the same as that in previous recordings attributed to Abu Musab al-Barnawi, the leader of ISWAP and the son of Boko Haram’s founder Mohammed Yusuf.
In the audio, the voice, which speaks in the Kanuri language, says that ISWAP soldiers were told to “take urgent action” against Mr. Shekau by “Amirul Muminin,” referring to the leader of ISIS, according to Mr. Salkida.
ISWAP fighters engaged Mr. Shekau in gunfire, after which he ran away and hid in the bush for five days, the audio said. But the fighters tracked him down.
“Our fighters sacrificed their lives and were in a state of fear, thinking that it was an impossible mission to achieve,” the message said. “He was actually caught unawares.”
Ismail Alfa contributed reporting from Maiduguri, Nigeria.