46. Penal proceedings for offences under this Act or the regulations are prescribed after the longer of
(1) five years from the date the offence was committed;
(2) two years from the date on which the investigation that led to the discovery of the offence was begun if false representations were made to the Minister or to a functionary or investigator.
In the cases referred to in subparagraph 2 of the first paragraph, the Minister’s or investigator’s certificate constitutes, in the absence of evidence to the contrary, conclusive proof of the date on which the investigation was begun.