Companies behind software used by millions to swap music, movies and other files online could be on the receiving end of warnings or even legal action by US attorneys general, according to a letter apparently drafted by California Attorney General Bill Lockyer.

　　The letter, which was cited in published reports on Monday and circulated by a trade group representing file-sharing software firms, warns that the states' top law enforcement officers have set their cross-hairs on the purveyors of so-called peer-to-peer programs.

　　The added state scrutiny could spell potential trouble for the file-sharing firms, who have thus far survived the sort of legal challenges from the entertainment industry that sank the original Napster service in 2001.

　　"Over the coming months, we will begin focusing more attention on the risks P2P software programs pose to consumers in our states," the letter said. "We take seriously our responsibility to protect consumers and ensure that the laws of our states are respected. In the future, we will not hesitate to take whatever actions we deem necessary to ensure that you fulfill your duties as a responsible corporate citizen."

　　Outlined in the letter are concerns that the software companies have not done enough to curtail the unauthorized distribution of movies, music, software, video games and pornography. The letter also questions whether the firms have made it clear to users that they could be held liable for sharing copyright works, or that they could contract a computer virus or be susceptible to identity theft by using their software.

　　"A failure to prominently and adequately warn consumers, particularly when you advertise and sell paid versions of your software, could constitute, at the very least, a deceptive trade practice," the letter said.

　　Lockyer spokesman Tom Dresslar did not confirm or deny the draft of the letter originated in his office. But he acknowledged that Lockyer, who is the president of the National Association of Attorneys General, has worked on the issue with his counterparts.

　　"The attorney general is concerned about several issues related to P2P file-sharing," Dresslar said. "And he is working with his colleagues in other states to address those issues."

　　P2P United, which represents several file-sharing software distributors, including StreamCast, the firm behind the Morpheus program, responded to Lockyer's purported draft with an offer to brief him on the industry.

　　"We are concerned that misinformation and partial information could rapidly escalate into state-based proceedings or activities," said Adam Eisgrau, the trade group's executive director.

　　In his letter, Eisgrau also pointed out that formatting information saved in the draft letter suggested that Vans Stevenson, a senior executive with the Motion Picture Association of America, had a hand in it.

　　Stevenson denied writing the letter, but said Lockyer sought input from the MPAA about a month ago.

　　(The Associated Press)