A drug has been found in the blood of a lead investigator in the Brussels corruption scandal, and there's a strong probability that two other investigators have been poisoned with the same substance in Brussels.

The Brussels Public Prosecutor's Office has launched an attempted murder investigation in relation to the possible poisoning of three police officers, including one of the lead investigators of the Brussels corruption scandal.

"We inform you that a complaint has been made for attempted murder. Due to the interests of the investigation, we cannot provide further details on the case," the prosecutor's office communicated on Thursday in response to an inquiry from Politico.

Last month, three police officers were arrested after causing a significant disturbance at a bar in the center of Brussels, where they were involved in a drunken brawl.

On the night of the arrest, one of the officers was hospitalized with internal bleeding and underwent abdominal surgery. Blood tests revealed that there was a high dose of amphetamine in his system, reported the Belgian newspaper Het Laatste Nieuws.

A massive dose of amphetamine was still present in the man's system 12 hours after the events. He does not recall that night at the cafe, nor do his colleagues. A law enforcement official, who spoke to Politico on the condition of anonymity, said that the police will soon examine the other officers as well since there are suspicions that they might have been drugged with the substance as well.

The corruption scandal in Brussels has been the subject of an ongoing police and prosecutorial investigation. The inquiry deals with corruption allegations that have surfaced in the European Parliament and involves attempts at influence peddling by countries such as Qatar, Morocco, and Mauritania.