UPDATE: 11:40 After further investigation, Police determined the threat towards the school was not credible. The lockout has been lifted and all activities have returned to normal before lunchtime.
Norman High School is currently under lockout after receiving a threatening phone call, according to Norman Police.
All the exterior doors are locked and all students brought inside.
Police have not released the nature of the phone call yet.
Students will continue class schedule as normal. Stay with OU Nightly as this story develops.