(CNN) -- To many who watched his long, rambling video statement, Boko Haram leader Abubakar Shekau appeared strangely distracted, unfocused, perhaps under the influence of drugs while boasting of abducting nearly 300 Nigerian schoolgirls. But there is calculation in such cruelty, and method where some see madness. The kidnapping serves Shekau on many levels, and observers of Boko Haram say he should not be underestimated. Shekau's on-camera performances are the opposite of the composed appearances of late al Qaeda leader Osama bin Laden and the terror group's current chief, Ayman al-Zawahiri. Jacob Zenn, an expert on Boko Haram with the Jamestown Foundation, a Washington, D.C.-based research and analysis firm, says Shekau has even acknowledged the intellectual chaos of his presentations. But they impress his followers.
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Abubakar Shekau is ruthless when dealing with dissent among his followers
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He took the reigns of Boko Haram after the death of Mohamed Yusuf in 2009
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Some analysts wonder if kidnapped girls will be used as bargaining chips
Twice wounded himself -- in 2009 and 2012 -- @placeholder appears to revel in violence.