Three people were arrested in a raid on three properties in Cospicua on Tuesday in relation to illegal activities.
Drugs, police radio scanners and other items were found after an operation on following days of observation.
Police only revealed the raid on Friday, saying that it was led by the major crimes unit but also included the special intervention unit, the drugs squad and the dogs section.
Officers from the animal welfare department assisted in the operation as seven dangerous dogs were being kept at one of the sites.
Assistant Commissioner Sandro Gatt, who leads the major crimes unit, said the operation showed how the police work together to fight any form of criminality.
Video: CMRU, Malta Police Force