"Domestic Islamist extremists were responsible for only one of the 50 killings documented in 2018, a sharp drop from recent years and the lowest figure since 2012, the last year when no such killings took place. Unlike the last several years, there was no domestic Islamist extremist mass casualty event such as a shooting spree or vehicular attack in 2018. Compared to right-wing extremists, domestic Islamist extremists in the U.S. have been involved in far fewer lethal incidents—but a number of those attacks have been high-casualty events, including most notably the Pulse nightclub attack in Orlando, Florida, in 2016, which left 49 dead. The fact that only one person was killed by a domestic Islamist extremist in the U.S. in 2018 should not be taken as an indication that the threat posed by this form of extremism has diminished. A number of domestic Islamist extremists were arrested in 2018 for a variety of crimes, from terrorist plots to providing material support to terrorism."