D'Iberville High School students returned to class about 30 minutes after being evacuated due to a bomb threat Thursday morning.
Deputy Chief Clay Jones said students returned to class after an extensive sweep done by the bomb squad.
"We take every threat seriously," he said. "Their safety is the top priority."
Jones said officers went through the building to make sure there were no devices on the property before anyone was allowed back in.
"Now, we enter the second phase where we will begin to try and figure out who made the threat," he said.
Officials have not released how the threat was made.
Sunherald.com will update this story as more information becomes available.