Trial after a person ceases to be subject to naval law

    When any offence mentioned in this Chapter has been committed by any person while subject to naval law and such person has since the commission of the offence ceased to be subject to naval law, he may be taken into and kept in custody, tried and punished under this Act for such offence in like manner as he may have been taken into and kept in custody, tried and punished if he had continued subject to naval law:
     Provided that he shall not be tried for such offence except in the case of an offence of mutiny or desertion, unless the trial against him commences within six months after he has ceased to be so subject.