FBI investigators have been logging into Second Life to check out the casinos dotted around the virtual landscape. 

Second Life creator Linden Lab has invited the FBI to investigate the situation in an attempt to seek guidance concerning the rather murky topic of gambling in the virtual world. 

What makes the topic so controversial is that, although the gambling happens in a virtual environment, users can exchange currency in Second Life, known as Linden dollars, for real US dollars.

"We have invited the FBI several times to take a look around in Second Life and raise any concerns they would like, and we know of at least one instance that federal agents did look around in a virtual casino," said Ginsu Yoon, vice president for business affairs at Linden Lab.

It is believed that gambling in Second Life has skyrocketed following the US crackdown on online gambling and companies that enable online gambling.

The US anti-gambling statutes cover the wagering of 'something of value' and as the Linden dollar has a direct correlation to a real world value, most lawyers agree that it does violate these laws.

However no-one seems sure how much Linden Lab, which has rules to prohibit illegal activity, could be held responsible as it has no way of monitoring the casinos in Second Life.

"It is not always clear to us whether a 3D simulation of a casino is the same thing as a casino, legally speaking, and it is not clear to the law enforcement authorities we have asked," Yoon said.