HAMPSTEAD, North Carolina - Authorities say reports of active shooter at a school in North Carolina turn out to be malfunctioning heater.

Pender County emergency management director Tom Collins says a noise from the water heater was taken for the sound of gunfire at Topsail High School Friday morning. 

Earlier report of shots fired provoked a massive response by law enforcement and caused the school district to reroute buses and put schools on lockdown.

Captain James Rowell of the Pender County Sheriff's Office says deputies swept the school but found no evidence that any shots had been fired.

He said deputies did find an HVAC unit that was malfunctioning and making sounds similar to gunshots.