Bangladesh, Aug. 25 -- Europe is facing a disturbing transformation in the way organized criminals target museums, with increasingly brazen gangs abandoning traditional methods of art theft in favor of violence, explosives and direct confrontation. A new report from Europol warns that museum robberies are becoming more aggressive as criminals focus less on irreplaceable works of art and more on gold, precious metals and gemstones that can be quickly converted into cash.

The report, titled Changing Tactics, Changing Targets: The Evolving Nature of Museum Heists, describes a significant evolution in cultural-property crime. Historically, museum theft was often associated with careful planning, deception, insider assistance and discreet ope...