An officer has filed a formal report after being threatened by colleagues attempting to unmask the overtime racket whistleblower, senior police sources say.

The policeman had left the traffic unit after a disagreement with the sergeant who is suspected of coordinating widespread abuse that saw officers claiming pay for jobs they never carried out.

Since news of the investigation emerged, the former traffic unit officer has been bombarded with threats and abusive messages accusing him of being the whistleblower.

The officer has become so concerned that he has filed an official harassment report. Since the investigation, which also includes claims of fuel theft, was revealed by Times of Malta last week, the traffic section has been decimated as almost every officer has been implicated.

So far, 25 officers have been suspended and a further seven resigned, including the superintendent responsible for the unit and some of its most decorated officers.

While 31 officers are on police bail, no one has yet been charged. 

The investigation was triggered by a letter from the whistleblower to former police commissioner Lawrence Cutajar in December last year.

“The officers in the traffic unit believe that a particular officer had been the one to expose them and he told me himself that he has been receiving threats,” a police source said.

Meanwhile, investigators said the probe was focusing on designated duty officers – the men and women in charge of assigning overtime to their subordinates – in a bid to find out how widespread the abuse was. 

Officers had their monthly salaries boosted to €3,000 by phantom overtime

Sources said the investigation had uncovered a large number of officers who had been taking home monthly salaries of up to €3,000, boosted by several hundred euros through phantom overtime. 

One source privy to the internal investigation said that, during interrogations, it had become clear that while some officers had only abused the system for a short while, others appeared to have been doing so for years. 

“The extra cost of this to the taxpayer will be difficult to calculate until we get to the bottom of how widespread it actually was,” a source said.

The scandal comes at a difficult time for the force, following Mr Cutajar’s resignation last month.

Three police units are investigating the claims about overtime abuse: the Economic Crimes Unit, the Criminal Investigation Department and the Internal Affairs Unit.