Chelsea have issued a £16million High Court claim against Norwegian club Lyn Oslo and their former chief executive Morgan Andersen over the transfer fee paid for Nigerian midfielder John Obi Mikel.
Chelsea issued a statement that said: "The claim is against FC Lyn Oslo and Morgan Andersen and follows the criminal conviction in Norway of Lyn's former Chief Executive Officer Morgan Andersen."
"It is now clear following Andersen's conviction that the transfer was based on the fraudulent misrepresentation that Mikel had an employment contract with Lyn.
"Chelsea has written to Lyn to make clear that because the transfer was based on a fraudulent misrepresentation, now proven by a court of law, the settlement previously agreed is not binding. Chelsea is in contact with Lyn and looks forward to working positively with them to resolve the claim promptly."
The Premier League club paid £16million for the Nigeria international in June 2006; £4million going to Lynn and £12million going to Manchester United after a long running legal battle over who had actually signed Mikel.
United had claimed they had signed Mikel from Oslo but they later agreed to terminate their option agreement when the player made it clear he wanted to join Chelsea.
However, the Blues made it clear that United were not involved in their High Court claim.
"Chelsea would like to make clear that this legal action is against Lyn and Morgan Andersen."