The Winklevoss brothers have re-started their long-running legal dispute with Facebook and its boss Mark Zuckerberg.
Just days after dropping a supreme court action, the twins filed a fresh lawsuit against the company.
It claims that Facebook "intentionally or inadvertently suppressed evidence" during their previous litigation.
Originally, Tyler and Cameron accused Mr Zuckerberg of stealing their idea to create the site.
The story of the feud formed the core of the 2010 film "The Social Network".
The row dates from 2003 when the Winklevosses hired Mr Zuckerberg to write code for their ConnectU site while at Harvard.
He never did, but instead set up Facebook, which quickly became a success around the world.
A court case over who did what was resolved in 2008 when the parties agreed on a financial settlement, reportedly worth around $65m (£41m).
In January 2011 the Winklevosses tried to reopen the case, seeking more money. However, a US appeals court ruled in April that they would have to accept the settlement.
The twins initially said they would appeal against the settlement, but decided this week not to pursue that legal avenue.
In the most recent suit filed on Thursday with the US District Court of Massachusetts, the Winklevosses and their business partner Divya Narendra said that Facebook hid some crucial information from them during settlement proceedings.
The twins said that Mr Zuckerberg did not disclose some important documents in regards to the relationship between him and the brothers while they were at Harvard.
Facebook's outside counsel Neel Chatterjee said in a statement: "These are old and baseless allegations that have been considered and rejected previously by the courts."