Riverview High School is Hillsborough County is currently on modified lockdown, according to Larry McKinnon, the sheriff's office PIO. 

McKinnon said someone thought they saw a gun on campus. 

The school was put on lockdown while deputies search backpacks, lockers, and the school grounds. 

McKinnon said so far they haven't found anything. 

This is a developing story, please check back for updates.