RUC officers yesterday had to wrestle a knife from a mental patient who burst into a school.
The 32-year-old man took the weapon from a member of the kitchen staff before locking himself in a store cupboard where he injured himself.
None of the pupils at Dalriada Grammar school in Ballymoney, Co Antrim, was hurt but headmaster Mr William Calvert said staff were left deeply shocked.
"The four staff who faced the intruder are at home being comforted by their families," he said.
One of the kitchen workers needed treatment for a cut to her arm after the patient grabbed the knife.
Most of the school's 980 pupils had not arrived for class when the man burst into the school at 8.30 a.m., but those who had were ushered into two halls well away from the danger.