Riverdale High School was on lockdown Friday morning after a student was found with a gun on campus.

Clayton County school police told Channel 2 Action News that the student was in custody.

Clayton school police Chief Clarence Cox told the station that officers found a loaded 9 mm handgun inside the school.

Cox said a campus security officer was attempting to detain the student for a separate offense, and when he resisted, the gun fell out of his pocket.

Charles White, spokesman for Clayton County Schools, told Channel 2 that the school was placed on lockdown as a precaution while the incident was investigated. The lockdown was lifted about 11:30 a.m.

“We do not know what the student’s intent was or if he/she just had the gun on their person,” White said.