Holly Area Schools heightened its security efforts after the school received a shooting threat on Wednesday.
The Oakland County ISD received an anonymous phone call on Feb. 12 stating "there would be a shooting today at a school district in Oakland County when school lets out," according to a letter from Holly Area Schools Superintendent Scott Roper.
The district put its buildings into secure mode just before and during dismissal time.
"During secure mode, we limit unnecessary hallway traffic and heighten security efforts for visitors checking into the buildings," Roper said.
The district also increased police presence around their buildings Wednesday afternoon during dismissal and during evening events.
The threat was deemed not credible by police, Roper said.
The Waterford Police Department is still investigating.