Russia’s military investigation department is in the final stages of closing the case on the theft of two 13 ton propellers from the Bespokoynyy a guided-missile destroyer.

The Sovremenny class destroyer was in dry dock, in Kaliningrad, according to The Drive. Kaliningrad is the heavily militarized Russian territory located between Poland and Lithuania and separated from Russia’s mainland. Kaliningrad is also home to Russia’s Baltic fleet.

The Bespokoynyy was being converted to a floating museum at the time of the incident.

Allegedly, a former commander of the ship was the ring leader in the plot to steal the bronze propellers. The motivation was financial. According to the Russian news outlet Interfax, the leader of the investigation department, Sergei Sharshavykh, confirmed the two propellers were worth around 39 million rubles, equating to about $523,000.

Sharshayykh has not released the names of the commander or his accomplices.

To “cover their tracks,” the thieves replaced the real propellers with fake counterfeit versions, the “cost and quality of which are several times lower” Sharshayykh told Interfax.

The exact time when the heist took place is not known. Sharshayykh said that the ship had been dry-docked at the Yantar Shipyard since 2016 to begin the decommissioning and conversion process. By 2018, the Bespokoynyy was fully decommissioned and serving as a museum, so the crime must have happened between 2016 and 2018.

Considering the coordination effort, equipment, and manpower needed to lift and move 26 tons worth of propellers, it’s hard to believe that Russian Navy and Shipyard personnel weren’t involved in the scheme.

Sharshayykh did not disclose what kind of prison sentences and fines the accused are facing.

This isn’t the first off-the-wall heist that the Russian military has experienced. A couple of months ago, there were reports that criminals stole communications equipment from a Russian Air Force Il-80 Maxdome. The Maxdome is a secret “doomsday aircraft” used to serve as a command post during major emergency events.

It’s unknown if any portion of the propellers has been recovered.