The Cameroon army says it has killed the leader of Boko Haram, Abubakar Shekau, whose movement is accused of thousands of civilian deaths and kidnappings since 2009. Shekau gained worldwide infamy after Boko Haram, a radical Islamist group, abducted 200 young school girls in Nigeria earlier this year. Shekau appeared with the girls in a video, prompting the #BringBackOurGirls campaign.

The Cameroon army released a statement Sunday that claimed Shekau was dead and included a photograph of a man who resembled him. The statement said Shekau was killed in an aerial bombardment near the Nigerian border town of Ngala in conjunction with a ground raid. The photo can be seen here via Ynaija, a Nigerian online newspaper.

Security forces have claimed to kill Shekau dozens of times since he became Boko Haram's leader in 2010 after the death of his predecessor. Most recently, the Nigerian military claimed it killed him last Wednesday, some 70 miles away from where the Cameroon army claimed to kill him on Sunday.

Shekau will often appear in videos to prove he is alive and to mock security forces for their failure. The Nigerian military is reportedly investigating the Cameroonian claim and an official reportedly said the dead man could be a body double.

Shekau and Boko Haram operate in a remote region spanning northeast Nigeria, northern Cameroon, southeastern Niger and western Chad. Their base of operations is in Nigeria's Borno province, where they have killed more than 5,000 people in the last four years and 2,000 in the first half of 2014 alone, according to Human Rights Watch. The group seeks to establish an Islamic caliphate.