Of all the terrorist leaders sending out suicide bombers in Africa, Boko Haram's Abubakar Shekau is probably the most globally recognizable: Who could forget that leering laugh as he boasted last year of kidnapping nearly 300 schoolgirls to use as "slaves"?
But where is Shekau now?
The Nigerian terrorist group has released several gory videos depicting killings in recent months – but Shekau hasn't been seen in one since March.
President Idriss Deby of neighboring Chad on Wednesday voiced what security analysts have suspected for months: Shekau no longer leads Boko Haram.
Is he dead? Sidelined? Severely injured? Deposed? Rumors suggesting all of the above have been swirling for months.
And if he is gone, does that mean Boko Haram -- which this year rebranded itself as Islamic State's West Africa Province -- is close to defeat?
Shekau has been declared dead many times by Nigerian authorities, only to pop up again. The latest rumor follows the death last September of Ahmed Abdi Godane, the leader of Somali terrorist group Shabab, and confirmation last month that Taliban leader Mullah Mohammed Omar died two years ago.
Both groups have fought on.
While analysts aren't sure what has happened to Shekau, or whether he has a successor, Boko Haram seems nowhere close to defeat. In recent months, the group has seen a resurgence, departing from its previous tactic of trying to rule a large chunk of northeastern Nigeria and reverting to attacking civilian targets such as markets, often using teenage girls as suicide bombers.
In a news conference Wednesday, Deby said Boko Haram had been "decapitated" after Shekau was severely injured in March during fighting in the Nigerian town of Dikwa.
"Who told you that Shekau is alive today?" Deby said rhetorically.
Deby didn't confirm Shekau's death, nor did he name a new leader. But he said a figure named Mahamat Daoud "speaks on behalf of the sect" and had called for negotiations with the Nigerian government.
"Certainly the fact that he has not been seen makes it credible or believable that he might have been replaced as leader," J. Peter Pham, analyst with the Atlantic Council, said of Shekau, adding that Chadian intelligence was in a position to know about his fate.
"On the other hand, they've had some spectacular failures in their intelligence as well," Pham said. "There have been at least four or five times when the Nigerians have announced he'd been killed. If he reappeared tomorrow I wouldn't be surprised."
The Chadian leader said Shekau had narrowly escaped being caught in March and Chadian forces knew at the time that he had been moved to the Nigerian town of Maiduguri.
"We informed our Nigerian friends, but unfortunately they did not want the Chadian forces to capture him," Deby told journalists, according to a transcript of the news conference. Troops from Chad have been part of a West African force combating Boko Haram.
Daoud is a mystery figure, so far unknown to analysts, according to Yan St-Pierre, director of the Berlin-based Modern Security Consulting Group.
St-Pierre describes Boko Haram as a loose umbrella group consisting of complex factions, each with its own leader, which cooperate at times on ideological, business and criminal grounds. It would be more accurate to say the group is led by a committee or council than by one dominant figure, he added. It's not even clear whether Daoud speaks for one small faction or a broader group.
"Really the crux of the problem is that Boko Haram is not a homogeneous group," St-Pierre said. "It's not a top-down organization structured in response to one leader. There are many factions and many groups that work together for ideological or business interests."
The group's fragmented nature and the mystery around Daoud make it difficult to assess whether negotiations with Boko Haram may take place – or whether Daoud's faction could even hold the bulk of Boko Haram fighters to any agreement, if he is indeed pursuing talks with the government.
There have been many unsuccessful efforts to negotiate with Boko Haram in the past. The latest was in October, when Nigeria's military announced a cease-fire accord after talks in Chad mediated by Deby on the release of the kidnapped schoolgirls in return for Boko Haram prisoners. But the deal came to nothing.
The man who claimed to be negotiating for Boko Haram at that point, Danladi Amadou, "turned out to be a complete fraud," Pham said.
Deby said Wednesday he would advise against negotiations with the terrorist group.
"The main issue is there's no formal representative of Boko Haram to say, 'We speak for the group,'" St-Pierre said.
He added that in recent months, Boko Haram appeared to have been getting significant support from Islamic State, after Shekau made the formal pledge of allegiance in March. Boko Haram has been mounting almost daily attacks in West Africa, suggesting the group was getting help from Islamic State with logistics and supplies, St-Pierre said.
Pham dismissed the impact of Shekau's fate on the group.
"Even if it turns out that Shekau is either dead or not in a position to lead Boko Haram, you would hardly call it a decapitation, considering the ability of the group to continue its operations, including in the last day a horrific attack on a cattle market," he said, referring to a suicide bombing Tuesday in the Nigerian town of Sabon Gari that killed at least 47 people, reportedly carried out by a female bomber.
"The group, in the last few months since Shekau's disappearance, has shown itself to be remarkably resilient with attacks not only in Nigeria but the Chadian capital, Niger and Cameroon."