Joltid and Joost, two companies owned by Skype founders Niklas Zennstrom and Janus Friis, filed a lawsuit in a Delaware court against former Joost chief executive Mike Volpi and Index Ventures, an investment firm seeking to buy Skype from eBay.

Volpi is a partner in Index Ventures and in the lawsuit filed on Friday he was accused of using his previous position at Joost, an online video portal, to "misappropriate" trade secrets used to put together the bid for Skype.

The complaint by Joltid and Joost was filed two days after Joltid named eBay, Skype and the group of investors who are seeking to purchase Skype from eBay as defendants in a copyright infringement lawsuit.

Joltid also filed suit against Skype in a British court in March.

EBay purchased Skype from Zennstrom, a Swede, and Friis, a Dane, in 2005 for a price tag that eventually exceeded 3.1 billion dollars and the pair have been reportedly seeking to buy back the company which made them billionaires.

EBay, however, announced two weeks ago it is selling a 65 percent stake in Skype to private equity firm Silver Lake Partners, London-based Index Ventures, the Canada Pension Plan Investment Board and venture capital firm Andreessen Horowitz for some two billion dollars.

There was no immediate comment from Volpi or Index Ventures on the latest lawsuit but eBay dismissed the previous complaint as "without merit" and said it expected the sale of Skype to go ahead as scheduled.

Skype, which has its headquarters in Luxembourg, bypasses the standard telephone network by channeling voice and video calls over the Internet.

It allows users to call others free of charge and provides the ability to connect with land lines or mobile devicesat low rates.