Art thieves have also shifted their attention to precious metals, jewels and cultural artefacts that offer greater profits, the EU's law enforcement agency said in a report

Art thieves across Europe are turning to increasingly violent stategies as specialized gangs are replaced by informal opportunists recruited via social media, Europol reported on Monday.

A high-profile raid at the Louvre Museum in Paris last October demonstrated this transition, Europol said, as robbers threatened guards and visitors before escaping with €88 million in jewels, including Empress Eugenie’s tiara.