When a criminal court and a Security Force Court have each jurisdiction in respect of an offence, it shall be in the discretion of the Director-General, or the Inspector-General or the Deputy Inspector-General within whose command the accused person is serving or such other officer as may be prescribed, to decide before which court the proceedings shall be instituted, and, if that officer decides that they shall be instituted before a Security Force Court, to direct that the accused person shall be detained in Force custody.