(New York, N.Y.) — President Joe Biden tonight confirmed the death of al-Qaeda leader Ayman al-Zawahiri yesterday in a U.S. drone strike in Kabul, Afghanistan.

To read the Counter Extremism Project’s (CEP) Ayman al-Zawahiri resource, please click here.

Zawahiri co-founded al-Qaeda with Osama bin Laden in 1988. He had led the group since bin Laden’s death in 2011 and expanded the number of al-Qaeda affiliates around the world. The FBI’s Rewards for Justice program offered a $25 million reward for information leading to Zawahiri’s capture.

Under Zawahiri’s stewardship, al-Qaeda became increasingly decentralized, with authority resting primarily in the hands of al-Qaeda’s affiliate leaders. Zawahiri brokered mergers with a number of Islamist groups including al-Qaeda in the Islamic Maghreb (previously the Salafist Group for Preaching and Combat or GSPC) and al-Shabaab. Zawahiri also sanctioned the creation of a number of al-Qaeda affiliates, including al-Qaeda in the Arabian Peninsula (AQAP) and al-Qaeda’s former Syria affiliate, the al-Nusra Front. In September 2014, Zawahiri announced the creation of al-Qaeda in the Indian Subcontinent (AQIS).

Before assuming the leadership of al-Qaeda, Zawahiri led the Egyptian Islamic Jihad (EIJ). Zawahiri merged the EIJ into al-Qaeda in June 2001. On August 6, 1988, the EIJ sent a fax to an Egyptian newspaper, stating that the terrorist group would seek revenge against the United States for arresting several of the group’s members. The following day, al-Qaeda bombed the U.S. embassies in Kenya and Tanzania, killing 224 people. The U.S. government indicted Zawahiri for his role in the attacks. In 1999, an Egyptian court sentenced Zawahiri in absentia to death for his role in an alleged terrorist plot against U.S. interests in Albania.

To read CEP’s Ayman al-Zawahiri resource, please click here.

To read CEP’s Al-Qaeda resource, please click here.