The FBI has arrested an Afghan man who officials say was inspired by the Islamic State and was plotting an Election Day attack targeting large crowds in the U.S., the Justice Department said Tuesday. Nasir Ahmad Tawhedi, 27, of Oklahoma City, Oklahoma, was arrested after the FBI discovered that he had been stockpiling automatic weapons and had taken steps to liquidate his family’s assets. After he was arrested, the Justice Department said, Tawhedi told investigators that he had planned an attack for Election Day that would target large gatherings of people.