
Colin P. Clarke (@ColinPClarke) is the director of research at the Soufan Group and a senior research fellow at the Soufan Center.
After hunting for him for 21 years, U.S. forces killed al-Qaida leader Ayman al-Zawahiri over the weekend with a drone strike targeting him at a safe house in Kabul, Afghanistan. Zawahiri had led al-Qaida since May 2011, when U.S. special operations forces killed Osama bin Laden in Abbottabad, Pakistan.