A gang of sophisticated thieves targeting valuable antique books has been broken up, Europol reported in The Hague on Thursday.
Nine Georgians have been arrested in raids in Georgia, Latvia, Estonia, Lithuania and France, the European Union's law enforcement agency said.
The gang is held responsible for the theft of at least 170 books, causing damage of around €2.5 million ($2.7 million) "and an immeasurable patrimonial loss to society," Europol said.
Some of the books had been sold at auction in St Petersburg and Moscow, "effectively making them irrecoverable," it said. The thieves had focused on rare books by Russian authors, such as first editions by Pushkin and Gogol.
Around 100 agents were deployed in Georgia and Latvia on Wednesday, searching 27 locations. They secured 150 books to look into their provenance.
Describing the gang's modus operandi, Europol said the thieves would visit libraries to ask to see the antique books and would then take photos of them and measure them up carefully.
Weeks, or even months later, they would return to make a similar request, this time to swap carefully made copies for the antiques. "Experts have established that the copies were of outstanding quality," Europol said.
In other cases, they would simply break in to steal books they had inspected in the past.
The international investigation was launched following a request for information from France that prompted other countries to report stolen books.