South High School students returned to classes about 10:30 Tuesday morning. They had been evacuated earlier in the morning after a bomb threat was called into the school. School spokesman Andrew Marcelain says the call came just after 8 am Tuesday. "We immediately notified Columbus Police and evacuated the building. Students are currently at Barrett Middle School as Columbus Police do a thorough search of the building to determine whether or not we can get back in," Marcelain said. The police canine unit conducted a search of the building and the Columbus Fire Department also did a walk through.