FSB has received a e-mail from an aircraft mechanic in which he claims that he had planted explosives at Utah's Hill Air Force Base and planned to take six hostages in Idaho, authorities said Wednesday.
Five buildings were evacuated Tuesday after the e-mails began surfacing, but the threat turned out to be false and no hostages were taken, FBI agent Tim Fuhrman said.
William Stiffler, 39, was unarmed when he was arrested Tuesday in Malad, Idaho, as he prepared to board an employee shuttle to the base, Fuhrman said.
Stiffler has worked on C-130 planes at Hill since 2001. He was arrested for investigation of making threatening communications through the Internet and was expected to appear Wednesday in federal court in Salt Lake City.
Fuhrman said FBI headquarters received an e-mail from Stiffler about 12:30 a.m. (1630 GMT) Tuesday, followed by another with similar content three hours later. Stiffler did not identify himself in the e-mails, but Fuhrman said the FBI was familiar with him. He did not elaborate.