I asked the SPF on Facebook, I got replied:
It will really depend on the nature of each case. Generally
police will need to ensure that any evidence or proof provided by
any complainant is not tampered with during the course of our
investigations.
Then it later was modified to:
Generally police will accept any information and proof
provided by a complainant who lodges a police report for a crime.
However, the evidence provided will be verified in the course of
police investigation. You may find out more about police
investigation on page 20 and 21 of the following e-informaton
booklet.
But I guess it will depend on the investigation
officer-in-charge.