The attack was the second-deadliest mass shooting in California after the 1984 San Ysidro McDonald 's massacre . It was also the deadliest mass shooting in the U.S. since the 2012 Sandy Hook Elementary School shooting , and the deadliest terrorist attack to occur in the U.S. since the September 11 attacks , until both categories were surpassed by the 2016 Orlando nightclub shooting six months later . Malik was one of a small number of female mass shooters in the U.S. ; women constituted only 3.75 percent of active shooters in the U.S. from 2000 to 2013
September 11 attacks
September 11 attacks
Rizwan Farook and Tashfeen Malik