CHURCH HILL, Tenn.—Students at a Tennessee high school were evacuated Tuesday on the second day of classes for the year and bused to a local armory after a 911 caller claimed to be a gunman in the building, which authorities later said they believe was a “hoax.” Hawkins County Sheriff Ronnie Lawson said the call came in around 8 a.m., prompting a major response at Volunteer High School in Church Hill from area law enforcement agencies that turned up no suspect and saw no shooting injuries. Deputies responded immediately and began searching, with at least five agencies involved, authorities said. The school evacuated all the students, marching them in lines with their hands over their heads to school buses, and they were taken to an armory to be reunited with their parents, said the county’s director of schools, Matt Hixson. Other schools locked down temporarily as a precaution. Local authorities, …