Guns, drugs and cash were also discovered in nine properties. Police from the Santiago task force made 10 arrests as part of a long-running investigation into firearms and drug trafficking.

Detective Inspector Stephen Denis of the Santiago group said the guns recovered in Thursday's raids included two pen pistols and two sawn-off shotguns.

Police also found two stolen cars, two stolen motorcycles and car parts.

The Santiago task force, formed in 2008, has investigated about 130 cases including several driveby shootings in Melbourne's west in which shots were fired into houses and cars.

Det Insp Denis said investigations leading to Thursday's operation, Indulge, began last November.

He said no charges had yet been laid and two of the men arrested had been released.

Det Insp Denis said the 25cm-long crocodile captured in an Essendon flat remained in custody.