The hijackers were led by Ziad Jarrah, a member of al-Qaeda. Jarrah was born in Lebanon. He moved to Germany in 1996, enrolling at the University of Greifswald to study German. He also started dating a German-Turkish dental student named Aysel Sengün. A year later, he moved to Hamburg, Germany and began studying aeronautical engineering at Hamburg University of Applied Sciences. While living in Hamburg, Jarrah became involved with a group of radical Islamic terrorists. This group was known as the "Hamburg Cell."