ESPN can reveal that Chelsea are conducting an internal enquiry, led by independent legal counsel, to determine whether the club should go ahead with a formal complaint to the FA regarding the conduct of referee Mark Clattenburg.
Chelsea are eager to satisfy themselves that they have a legally enforceable case before carrying on their formal complaint. The club have so far only complained to the match observer, and not, as yet, formally to the FA.
ESPN understands that owner Roman Abramovich and the club's hierarchy have given this internal enquiry high priority to establish firm ground for a complaint, given that Clattenburg is mounting a strong defence of his own, and that allegations now exist over a confrontation with the referee after the match in the changing rooms.
Key to the club's next step will be the delivery of the assessment of how strong their case is against Clattenburg. The legal team are conducting vigorous interviews and assessing written evidence from the players involved.
John Obi Mikel, Juan Mata, Ramieres and David Luiz are the players at the centre of the alleged "inappropriate language" used on the pitch. The two Brazilians told Mikel of the comment made to him by the referee, while Mata was also allegedly singled out for a verbal abuse.
Regardless of whether Chelsea feel they are on firm ground to persue a formal complaint, the Football Association will not be deflected in their own enquiries. The FA are moving at rapid speed in gathering the evidence on the Clattenburg case, and have not been delayed by the police investigation into the incident.
ESPN can disclose that the Metropolitan Police have been in touch with the FA, but did not request the governing body halt their own investigation and possible disciplinary action.
After discussions between the FA and the police, the FA are continuing to collate all relevant evidence before deciding whether to bring any disrepute charges, not only against Clattenburg, but also Chelsea players for the alleged incident in the referees' changing rooms after the game.
The FA were universally pilloried for being forced to put their enquiries into the John Terry/Anton Ferdinand disciplinary issue when the police brought charges that were dealt with in the Magistrates court.
That caused a delay that lasted virtually a year before Terry was banned for four games. This time, the FA are keen to press ahead as quickly as possible with their own investigation ahead of any police action.
If the police brought charges, it would then become a legal issue for the FA to decide what action to take, if any, or allow the police to persue the case, as happened with Terry.
Players union leader Gordon Taylor has already voiced his concerns over any similar delay in dealing with allegations of a racial nature involving Clattenburg, which the referee strongly denies.
The FA have received reports from Clattenburg's two assistants, and are now taking a personal statement from Clattenburg himself. However, they are refusing to confirm the format of their enquiries or just how quickly they plan to make a full statement on the issue.