The legal wrangling between Apple and Mac clone-maker Psystar is heating up this week. Documents filed with the court on Tuesday show that Apple believes Psystar may have backers involved with the company and Apple wants to know who they are.

Judge dismisses Psystar antitrust lawsuit against Apple

"On information and belief, persons other than Psystar are involved in Psystar's unlawful and improper activities described in this Amended Complaint," the court documents read. "The true names or capacities, whether individual, corporate, or otherwise, of these persons are unknown to Apple."

The amended complaint adds John Does one through 10, representing up to 10 more defendants that Apple can add to the lawsuit. Lawyers for Apple said the complaint will be updated with the true names and capacities of the John Does when they are known.

Apple sued Psystar in July 2008 claiming the company violated its copyrights and licensing agreement when it sold a computer with Mac OS X installed on it. Apple's end-user licensing agreement forbids Mac OS X from being installed on non-Apple hardware.

On Monday, Judge William Alsup granted Apple's motion to amend the complaint against Psystar to add a Digital Millennium Copyright Act claim. In filing the amended complaint Apple said they had discovered additional information since the original complaint was filed. Without going into detail, lawyers said the new information is in regards to Psystar's products and marketing.

In mid-November Judge William Alsup dismissed a Psystar lawsuit against Apple alleging the Cupertino, Calif. company violated federal and state antitrust laws.

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