A refuse collector who worked for the Sliema council is facing bribery charges, The Sunday Times has learnt, and yet another local councillor is under investigation.

Sources said the charges against the refuse collector were in connection with former mayor Nikki Dimech, who was charged with bribery last year. Mr Dimech pleaded not guilty.

It is not clear if Mr Dimech is facing more charges or whether a separate councillor is under investigation. Local councillor Patrick Pace was also questioned in the first police investigation.

Three other Sliema councillors are facing criminal charges – Cyrus Engerer, Martin Debono and Yves Bobby Calì.

Mr Engerer was recently charged with maliciously circulating pornography involving his ex-boyfriend.

Meanwhile, Mr Debono and Mr Calì were charged over suspicious behaviour regarding two council laptop computers, which they had returned devoid of their hard drives. When contacted for comment, the police said: “Please be informed that court charges have been issued against three Sliema councillors and a refuse collector. Once one of these cases is concluded, criminal action will follow against another councillor. No further details can be disseminated as cases are still sub judice.”

The police refused to give further details when asked to specify the identity of the three councillors.

The three as well Mr Dimech have resigned from their parties and now sit as independent councillors.

Investigations into the council began last year when the authorities noted a number of irregularities in council documentation. The police became involved at a later stage and have in the past months filed charges.

Given the unrest, the government recently said it was monitoring the traditionally Nationalist council to see whether it is still functioning efficiently or if it should be dissolved.

Besides the four councillors facing criminal charges (three of whom were originally Nationalist members), former Nationalist Sandra Camilleri had also resigned from the party last year.