89Arrest without warrant

89  Arrest without warrant  (1) A member of the Defence Force may, without warrant, arrest a person over whom the member has a power of arrest if, and only if, the member believes on reasonable grounds:  (a) that the person has committed, or is committing, a service offence;  (b) that the arrest of the person is necessary in order to achieve one or more of the following purposes:  (i) the purpose of ensuring the appearance of the person before a service tribunal in respect of the service offence;  (ii) the purpose of preventing a continuation of or repetition of the service offence or the commission of a further service offence;  (iii) the purpose of preventing the concealment, loss or destruction of evidence of, or relating to, the service offence;  (iv) the purpose of preserving the safety or welfare of the person; and  (c) that proceedings under section 87 against the person in respect of the offence would not effectively achieve that purpose or those purposes.  (2) For the purposes of subsection (1):  (a) an officer has a power of arrest over:  (i) a sailor, soldier or airman;  (ii) an officer in respect of whom he or she is a superior officer; or  (iii) a defence civilian;  (b) a warrant officer or a non‑commissioned officer has a power of arrest over a sailor, soldier or airman in respect of whom he or she is a superior officer;  (c) a member of:  (i) the regulating staff;  (ii) the staff of the officer of the watch; or  (iii) the staff of the officer of the day;   of a ship or establishment of the Australian Navy has a power of arrest over any sailor;  (d) a police member or a person lawfully exercising authority under or on behalf of a service police officer has, subject to the regulations, a power of arrest over any person; and  (e) where the service offence concerned is mutiny or a service offence involving disorderly or violent behaviour:  (i) an officer has a power of arrest over any other officer; and  (ii) a warrant officer or a non‑commissioned officer has a power of arrest over any other sailor, soldier or airman.  (3) A power of arrest under subsection (1) may be exercised:  (a) personally;  (b) by ordering the person concerned into arrest; or  (c) by giving an order for the arrest of the person concerned.  (4) Nothing in subsection (1) authorizes the arrest, without warrant, of a person who is not a defence member or a defence civilian.  (5) A constable may, without warrant, arrest a person who the constable believes, on reasonable grounds, is escaping from custody or has escaped from custody to which the person is still liable.