The United States International Trade Commission (ITC) has begun an investigation of Nokia's complaint that Apple infringed its patents.

According to the ITC's website, the investigation, covering seven different patents, is set currently as being in the discovery, or initial phase, and so is listed as 'pending before the commission'.

Nokia first filed its claim with the ITC in December, but also has a lawsuit in court, claiming that Apple had used technology originally patented by Nokia for GSM, UMTS and WLAN technology (2G, 3G and Wi-Fi connections) on mobile phones. That covers all Apple's iPhones. If found guilty, Apple faces a large fine.

At the time it filed suit, Nokia said in a statement: "The basic principle in the mobile industry is that those companies who contribute in technology development to establish standards create intellectual property, which others then need to compensate for.

"Apple is also expected to follow this principle. By refusing to agree appropriate terms for Nokia's intellectual property, Apple is attempting to get a free ride on the back of Nokia's innovation."

Apple fires back

Two months after the lawsuit, Apple fired back at Nokia, claiming that Nokia had appropriated 13 ideas Apple developed in the iPhone.

At the time, Apple's General Counsel Bruce Sewell ratcheted up the rhetoric by saying: "Other companies must compete with us by inventing their own technologies, not just by stealing ours."

Nokia responded with the ITC complaint.

So who's the thief and who's the victim? Time, and some very heft legal fees, will tell.