Alan Filion, believed to have operated under the handle “Torswats,” admitted to making more than 375 fake threats against schools, places of worship, and government buildings around the United States.

Alan W. Filion, 18, of California, called in false reports of bombings and mass shootings across the country, the authorities said.

Federal prosecutors say a California teenager pleaded guilty in a case involving the swatting of a Florida mosque, among other institutions and individuals.