Tahrif, or Tahreef, is the Arabic word for "corruption." The term is used to reference a conspiracy theory dating back to the 9th century CE, which claims that Christians and Jews made changes to their religious texts... Read more

Ramadan Shallah was the leader of the Palestinian Islamic Jihad (PIJ) group from 1995-2018. Under his leadership, PIJ was responsible for numerous attacks on Israeli citizens and in 2007 he was placed on the FBI's Most Wanted... Read more

Ramzi Yousef is a Pakistani Al Qaeda operative who participated in several high profile attacks on behalf of the terrorist group. Yousef was the lead in the 1993 bombing of the World Trade Center in New York... Read more

Omar Mateen committed the Pulse Nightclub shooting on June 12, 2016, in Orlando, Florida, killing 49 and injuring 53. During and after the attack, Mateen stated that he was loyal to ISIS and that the recent killing... Read more

Abdullah Azzam (1941-1989) was an influential Palestinian Salafi jihadist who popularized the concept of 'defensive jihad' during the Soviet invasion of Afghanistan to encourage foreign volunteer fighters to travel to join the mujahideen movement. After the Soviet... Read more

Abdullah el Faisal is an extremist cleric who was convicted in February 2003 in the United Kingdom of inciting hatred against Jews, Hindus, Christians, Americans and others he considers "unbelievers." He first became an Imam in 1991... Read more

Abu Bakr al Baghdadi was an Iraqi terrorist and leader of ISIS during its period of territorial expansion in Iraq and Syria. He took over in 2010, and on June 29, 2014, he declared the establishment of... Read more

Crusaders is a term used by Islamists to refer to any Western presence in the Middle East, though it is most often used to refer to the U.S. In addition, anti-Muslim extremists in the United States often... Read more

Adam Yahiye Gadahn was born Adam Pearlman in Oregon in 1978; his father changed their last name to Gadahn after converting to Christianity. Adam later converted to Islam and quickly radicalized— he was arrested in 1997 for... Read more