Games such as World of Warcraft, Project Entropia and Everquest provide a likely avenue for criminals, as characters and equipment can be sold on the black market for real cash - often in excess of £5,000.
"The police are really good at understanding 'someone stole my credit card and ran up a lot of money'. It's a lot harder to get them to buy into 'someone stole my magic sword'," Microsoft engineer Dave Weinstein told Reuters news agency.
Massively multiplayer online role playing games (MMORPG) are enormously popular, and have been the subject of increasing scrutiny as their inherent value has increased. Norrath, the fictional setting for Everquest, has been rated as the 77th richest country in the world, coming between Russia and Bulgaria.
Last year Sony launched the Sony Station Exchange, where players of EverQuest can legally trade in-game cash, magical items and characters, while earlier this year Project Entropia announced it would issue a real-world cash card, linked to gamers' online characters.