Nestled alongside ISIS leader Abu Bakr Al Baghdadi in the deepest ranks of the depraved, Al Qaeda’s chief Ayman Al Zawahiri is one of the two most wanted men in the world – both have a $25 million U.S. bounty on their heads.

But while much has been speculated about when it comes to the barbaric Iraqi man Al Baghdadi, little is known about the Al Qaeda commander who has evaded his big bounty since it was installed immediately following the September 11 attacks.

“Zawahiri was a conspirator of the 9/11 attacks, and like other conspirators, will always be wanted by the United States,” said Rita Katz, Executive Director of the SITE Intelligence Group. “Zawahiri has framed himself more as the wiser alternative to Baghdadi and ISIS, who he characterizes as naïve and irresponsible.”

So who exactly is the elusive Zawahiri?