Born in Saudi Arabia, he studied Islamic law, or shariah, at King Khaled University in the city of Abha, in the southern Saudi Arabian province of Asir. He is also reported to have been a prayer leader, or imam, in one of the mosques there, and was reported by his family to have become very religious sometime in early 1999. He left home in the summer of 2000 to go on pilgrimage to Mecca and never returned, his family last having a call from him in May 2001, the same month he entered the United States. In America he stayed in an apartment with Saeed Alghamdi, another alleged hijacker, in Delray Beach, Florida. On September 11, 2001, he was apparently part of the four-man team that hijacked United Airlines flight 93, with Ziad Jarrah, Saeed Alghamdi, and Ahmed Al Haznawi, which was thwarted by passengers before crashing into a field near Shanksville, Pennsylvania at 10:03 A.M.
His family in Saudi Arabia has claimed that "he was an ordinary guy who couldn't do this awful thing" and went on to say that they couldn't be sure that he was even dead.