(Bloomberg) --

Around 20 police divers searched the waters of Berlin’s Landwehr Canal on Sunday as part of the investigation into the 2019 looting of treasures from Dresden’s famous “Green Vault.”

Officers secured the immediate surrounding area and the operation was likely to “take some time,” police in the state of Saxony, where Dresden is the capital, said in a statement.

They said they were unable to provide further information, including on whether the search had yielded positive results.

German authorities announced last weekend that they had recovered 31 items in Berlin that represented a “significant part” of the Dresden artifacts.

The initial haul included a diamond-encrusted dagger, a pearl necklace, and dozens of other pieces estimated by German media to be worth more than $1 billion.

It later emerged that the state of Saxony carried no insurance on the jewels, which it said was standard practice because the premiums typically exceed potential losses over the longer term.

The Dresden incident was one of a number of heists carried out at German museums in recent years. In November, thieves broke into a museum in Bavaria and made off with nearly 500 ancient gold coins worth several million euros.

In 2020, a Berlin court convicted three men of stealing a 100-kilogram (220-pound) gold coin worth $4 million from a museum in the center of the German capital.

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