In a statement released on its web site the ministry said that Malkoc was suspected of committing a criminal act and that his future military career would depend on the results of the investigation.
Malkoc was in a group of eight persons arrested in a coordinated operation carried out by the Office for the Suppression of Corruption and Organised Crime (USKOK) and the Interior Ministry. The group was arrested on suspicion of drug abuse, conspiracy to commit crimes, forgery of tax stamps and illegal possession of weapons.
The police searched more than a dozen flats, houses and cars used by the suspects and discovered 200 grams of heroin, 28.5 kilograms of commercial and military explosive, eight anti-personnel mines, three hand grenades, two detonators for anti-tank mines, 30 metres of slow-burning fuse, two machine-guns, four automatic rifles, a semi-automatic rifle, a shotgun, an M-48 rifle, a flare pistol, a revolver and 3,000 bullets.
The weapons are believed to have been intended for sale.
Defence Minister Berislav Roncevic congratulated the USKOK, the Interior Ministry and the military police on their successful operation.