A man was arrested by the police in Zabbar after sachets with substances believed to be cocaine and heroin were found in his car.
The police said the car was stopped by officers from the Drug Squad and Rapid Intervention Unit, and the drugs were found together with an undisclosed amount of cash.
A 15-year-old girl was in the car with the man, the police said.
Searches conducted by the police in two Cospicua residences yielded a revolver and ammunition, and other items related to drugs, apart from more cash.
Magistrate Rachel Montebello is leading an inquiry.
The man will be arraigned on charges related to drug trafficking and with taking part in sexual activity with an underage girl.