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The top ISIS leader in West Africa is dead. He had claimed responsibility for an attack that killed four U.S. service members. The French government says it killed him in a drone strike last month. NPR's Eyder Peralta reports.

EYDER PERALTA, BYLINE: Adnan Abu Walid al-Sahrawi was once a separatist in the Western Sahara, but he moved south to Mali and Niger, where he became aligned with al-Qaida. In 2015, Sahrawi pledged allegiance to the Islamic State in Iraq and Syria. And in 2017, he gained worldwide notoriety when he claimed responsibility for an ambush in Niger that left four American soldiers dead. The U.S. designated him a global terrorist and put a $5 million bounty on his head. And as violence escalated in the Sahel, France also declared him enemy No. 1. French President Emmanuel Macron said his killing was, quote, "a major success in France's fight against terrorists."

ALEX THURSTON: But I think also these strikes, they make for good news and so forth, but they don't really produce a lasting drop in violence.

PERALTA: That is Alex Thurston, who studies Islamic extremism in Africa at the University of Cincinnati. He says France has been aggressively killing these militant leaders in the Sahel over the past year or so, but the violence keeps escalating. While Sahrawi was one of the top three leaders in the Sahel, Thurston says he was also more of a super bandit than a brilliant political strategist.

PERALTA: Definitely hard-line ideologically, but somebody who spent a lot of his time, you know, probably thinking about how to extort money from people and how to survive. So, yeah, somebody like that can be replaced.

PERALTA: So a big terrorist leader is gone, he says, but the violence, which has left thousands dead in Mali, Burkina Faso and Niger, is very likely to continue.

Eyder Peralta, NPR News, Cape Town. Transcript provided by NPR, Copyright NPR.