FBI investigators have visited Second Life's Internet casinos at the invitation of the virtual world's creator, Linden Labs, but have not yet decided on the legality of virtual gambling, according to CNET.

Hundreds of casinos offering poker, slot machines and blackjack can be found in Second Life, where the three largest poker casinos are earning profits of a modest $1,500 each per month, according to casino owners and people familiar with the industry.

The surge in Second Life gambling coincides with a crackdown in the real world by the U.S. government, which has arrested executives of offshore gambling websites.

Linden Labs could face criminal charges under the 1970 Illegal Gambling Business Act or the Unlawful Internet Gambling Enforcement Act. The latter, passed last year, takes aim at credit card companies and other electronic funds transfer systems that enable internet gambling.