Bribery and corruption - Where are the police?

For the past 3 weeks Trinidad and Tobago has been hit with a very confusing bribery scandal. A PNM (political party in power) councillor alleged that he paid bribes to 2 ministers. They have both vigorously denied the allegations, one has produced documents and cancelled cheques to prove that the payments were repayments of a loan. The councillor has retracted his allegations, then retracted the retraction. One minister has resigned while the matter is investigated. The other is still in place.

So - the PNM has just decided to "put the matter in the hands of the Prime Minister".
The opposition is demanding that the matter be sent (by the PNM) to the Fraud Squad.

Now the questions - if a man makes a PUBLIC STATEMENT that he committed a crime - where are the police? Why has he not been arrested for bribery (according to his own statement)?
Why does the matter need to be sent to the Police by the Government? Can the Police not investigate these claims on their own? Can the opposition not ask the police to investigate? Cannot any citizen?