Person surrendered by foreign State in respect of an offence not to be prosecuted or detained for other offences
17.  Where a person accused or convicted of an extraditable crime is surrendered by a foreign State, the person shall not, unless he has been returned, or has had an opportunity of returning, to that foreign State —
(a)be detained or tried in Singapore for any offence that is alleged to have been committed, or was committed, before his surrender other than the offence to which the requisition for his surrender relates or any other offence of which he could be convicted upon proof of the facts on which that requisition was based; or
(b)be detained in Singapore for the purpose of his being surrendered to another country for trial or punishment for any offence that is alleged to have been committed, or was committed, before his surrender to Singapore other than an offence of which he could be convicted upon proof of the facts on which the requisition referred to in paragraph (a) was based.