(b)where a person who is accused or suspected of the commission of an offence under this Act is forwarded to the Magistrate under sub-section (2) or sub-section (2A) of section 167 of the Code of Criminal Procedure, 1973 (2 of 1974), such Magistrate may authorise detention of such person in such custody, as he thinks fit, for a period not exceeding thirty days in the whole, where such Magistrate is a Judicial Magistrate, and seven days in the whole, where such Magistrate is an Executive Magistrate: