The litigation-prone RIAA, a trade group that claims to represent the US recording industry, has itself been accused of patent infringement by Altnet Inc, a Californian P2P firm.

Also in the firing line are several RIAA partners that make anti-piracy software products – Overpeer Inc., Loudeye Corp. and Media Sentry Inc. Loudeye acquired Overpeer in March this year.

Altnet filed the lawsuit in a Los Angeles district court last week. It alleges that RIAA and its partners infringed on Altnet’s patented file-matching technology that identifies file requests sent over a P2P network.

The suit claims that RIAA encouraged Loudeye and others to propagate popular P2P sites like Kazaa with bogus or damaged files that were disguised as user file requests. It also claims the methods used to match their files with users infringe its patented technology. Altnet is a close partner of Sharman Networks Ltd., the company behind Kazaa.

Woodland Hills-based Altnet is seeking an injunction to stop RIAA and its partners from further use of its patented technology.

It is also seeking monetary damages, but did not specify a dollar amount at this stage of proceedings.

In many ways the lawsuit is part of a concerted campaign waged by Altnet against a number of firms, including those in the current lawsuit, since last November when it issued a series of warning letters.

Altnet’s allies in the current suit include its parent company, Brilliant Digital Entertainment Inc. and Kinetech Inc. which developed the patented file request identification technology at the center of the lawsuit. Kinetech licenses the technology exclusively to Altnet and Brilliant.

Altnet certainly seems to have an axe to grind with the RIAA. The company also develops technology for the legitimate distribution of digital content via P2P networks. But this technology has been snubbed by major music labels and online content providers for the past three years. Altnet suspects that the RIAA and major labels have conspired against its efforts to get the technology licensed.