The incident happened on 7 January at a school in the Waterside area of Derry.Police were called to Oakgrove Integrated College after a 999 call saying a pupil was causing a disturbance.The boy, the school principal told police, had put his fist through a window and was being aggressive and abusive toward staff.A police sergeant who attended said he found the boy, who appeared angry and was bleeding heavily from his hand, pacing up and down the entrance foyer of the school.The officer told the Ombudsman's investigators he tried to reason with the boy, however, this had little effect and the pupil remained "very aggressive" before pushing and threatening him.After issuing a warning to the pupil the officer said he used CS spray in an attempt to calm him and resolve the situation.The student was then handcuffed and arrested.This was a first-class piece of policing where the reactions of an officer helped to resolve a difficult situation.Police Federation for Northern IrelandHe was given first aid by the officer for the effects of the spray and arrangements were made for the injures to his hand to be treated.The student was then taken to Strand Road police station where he was questioned in the presence of an older member of his family.The boy also apologised to the police officer.Police confirmed that CS spray, generally used by officers to control aggressors in situations where lethal force is inappropriate, was used during the incident.Following the Ombudsman's investigation, which included interviewing witnesses and examining CCTV footage, Dr Maguire said the officer did the "right thing".He said: "This young man had already hurt himself, was bleeding quite badly and needed medical attention."He had also threatened the officer and others and efforts to pacify him seemed to have failed."The officer said he feared for the boy's safety and the safety of others and had no alternative."No one who saw what happened, including the boy himself, is questioning his judgement."The Police Federation for Northern Ireland said it the Ombudsman's findings vindicated the action of the officer.In a statement the PFNI said: "This was a prompt investigation into an unfortunate incident in a school where an officer was pushed and threatened by a boy in a very aggressive state."The officer's response was proportionate, measured and correct and he is to be commended for his attempts to calm the agitated student."