(b)where a person accused of, or suspected of the commission of, an offence under this Act is forwarded to a 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 the detention of such person in such custody as he thinks fit for a period not exceeding fifteen days in the whole where such Magistrate is a Judicial Magistrate and seven days in the whole where such Magistrate is an Executive Magistrate: