Chelsea have lodged a High Court claim for £16million regarding their purchase of John Obi Mikel.
The Nigerian moved to Stamford Bridge in controversial circumstances in June 2006, with Manchester United and FC Lyn Oslo embroiled in a three way battle over the player's rights.
However, in the wake of a criminal conviction for Lyn's former chief executive officer Morgan Andersen, Chelsea have called for their substantial outlay to be reimbursed.
The Blues have lodged their complaint after it emerged that the transfer was based on the fraudulent misrepresentation that Mikel had an employment contract in Norway.
Chelsea, Lyn and Manchester United had agreed that once the relevant parties had received their fees then the issue would be closed and no further action would be taken in regards to the transfer.
That has proven to be impossible, though, as the news regarding Andersen places the saga in a whole new light.
"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," read a statement on the club's official website.
"Chelsea is in contact with Lyn and looks forward to working positively with them to resolve the claim promptly.
"Chelsea would like to make clear that this legal action is against Lyn and Morgan Andersen."