Priceline Group has been accused of “fraud in its absolute purest form,” relating to its acquisition of Momondo Group in a lawsuit filed today in Connecticut.

A press release has been issued by lawyers DiCello Levitt & Casey on behalf of its client Tersley.

It says that Tersley was an early investor in Cheapflights, and was in dispute with Highlander, which owned Momondo Group. The long-running dispute between Tersley and Highlander was settled shortly before the Priceline Group takeover of Momondo Group was announced.

The statement quoted Adam Levitt, Tersly’s legal counsel and a partner of DiCello Levitt & Casey.

“This is fraud in its absolute purest form…Priceline knew or should have known about Highlander’s involvement with Tersly through standard due diligence, including that Tersly had investment rights in any sale of Momondo/Cheapflights.”

“Rather than disclosing the pending transaction to Tersly, Priceline knowingly conspired with Highlander to negotiate a bad-faith settlement that terminated Tersly’s future investment rights – which would have been substantial, given Priceline’s position in the travel industry. Such a settlement was a small price for Highlander to pay to clear the way for a $550 million sale.”

More details to follow.