BALTIMORE (WJZ)— Baltimore City Public Schools Police arrested a family member of a student at National Academy Foundation Preparatory School on Monday.

The visitor had come to the school to deliver a birthday cake and balloons to her relative. She walked into the school without clearance and direction from the school office and was promptly intercepted by a school staff member, in keeping with school safety protocols.

An altercation ensued during which the visitor presented a knife.

Both the staff member and the visitor sustained hand injuries.

The staff member received medical treatment at a nearby hospital. The visitor was treated by ambulance attendants at the scene and then transported to Baltimore City’s Central Booking Intake Facility for processing.