Muhammad Ridzuan bin Mohd Ali v PP

To establish trafficking by possession for the purpose of trafficking under s 5(1)(a) read with s 5(2) MDA, the Prosecution must prove possession of the controlled drug (provable, presumed under s 18(1), or deemed under s 18(4)), knowledge of its nature (presumable under s 18(2)), and that possession was for an unauthorised purpose of trafficking; and the Public Prosecutor's discretion to issue a certificate of substantive assistance under s 33B is reviewable only for bad faith, malice or unconstitutionality.