§ Mr. McNamara
To ask the Secretary of State for Northern Ireland what powers he has to prosecute a civilian found(a) to be in possession of or (b) to have fired a stun grenade. 
§ Jane Kennedy
Dependent upon the precise circumstances of the case, a civilian would be likely to be prosecuted under Article 6 of the Firearms (Northern Ireland) Order 1981. Other Articles of the Order might also be relevant.