If Mark Clattenburg uttered a racist remark to Chelsea's John Obi Mikel, then his career as a referee died on the pitch as dusk fell at Stamford Bridge on Sunday.
If Clattenburg is innocent, as the elite refereeing community believe he is, then it is Chelsea who need vigorously calling to account by the FA. "Mark said nothing,'' insisted a leading official. Nothing.
The feeling among certain referees is that this is a trumped-up charge, that Clattenburg would never resort to such offensive, discriminatory language. They want the FA to address the matter today, moving swiftly to still the latest storm to buffet England's national game.
Chelsea dispute the referees' support for Clattenburg rigorously, alleging the Tyneside official called Mikel a " monkey" when booking him for dissent shortly after Javier Hernandez's controversial winner for Manchester United. Chelsea also infer that Clattenburg described Juan Mata as a "Spanish t**t".
Chelsea tempers were running high midway through the second half, the mercury sent spiralling skywards by Clattenburg decisions. He sent off Branislav Ivanovic correctly for bringing down Ashley Young.
Chelsea hit back off the pitch. They claim to have three players ready and willing to corroborate the testimonies of Mikel and Mata. It is understood one of their dressing-room number is known to be uneasy at his employer's aggressive stance towards Clattenburg.
Chelsea point out that Mikel went into the referee's room to confront Clattenburg. This is where the story becomes messy and confusing. The Nigerian is one of the more sanguine characters in the madhouse of English football, not an individual whose blood races quickly to boiling point, so something must have piqued him. But what? A misunderstanding of what Clattenburg said?
The truth will out: the mikes were open. Assistant referees Michael McDonough and Simon Long as well as fourth official Michael Jones will have heard what, if anything, Clattenburg said to Mikel and Mata. Officials are rallying to Clattenburg's defence.
He is popular. English referees appreciate the way he has joined Howard Webb in promoting their reputation across the globe. Fifa considered Clattenburg good enough to oversee the Olympic final at Wembley. He's a candidate for the 2014 World Cup finals in Brazil.
As well as being a referee considered "one of the elite in the world" according to the Premier League, Clattenburg is respected for the good deeds he does in the charity sphere. No fuss, no limelight. Clattenburg teamed up with fellow referee Mark Halsey to compete in this year's Great North Run to raise funds for a cancer charity.
Such efforts are all very admirable. Such backing from other members of the whistling community is terrific. But only the FA can fully ascertain whether Clattenburg made a racist comment. He vehemently denies the allegation.
By contrast, he is known within the game as being an official who attempts to engage with players, not being stand-offish like some of his colleagues.
Early in his career, on being fast-tracked by the FA who saw his potential, Clattenburg was arguably too friendly with players. Concerns were expressed by some of his colleagues that he was caught up in the glamour of working alongside such sporting celebrities. That was Clattenburg Mark I. He took time out, took wise counsel from more experienced referees, and re-emerged as a more considered official.
His maturing led to Clattenburg Mark II, bringing increased involvement in Fifa and Uefa competitions. Now, aged 37, Clattenburg appeared to have the balance right between working with the players, cajoling and sharing a joke, and controlling them.
It's not easy. Refereeing has never been more difficult. Officials must live with the perfect storm of quick, oft-cynical players racing from end to end in a game covered by 30-odd camera angles, instant replays for the commentators, and an unruly jury on the terraces and on Twitter. Modern referees need the wisdom of Solomon, the patience of Job, the probity of Caesar's Wife, the stamina of Mo Farah and the acceleration of Usain Bolt.
Oh, and the thick skin of a rhino. Oh, and good friends too.
Just as Chelsea have those ready to condemn Clattenburg, so the man himself has those ready to fight his corner. Referees love this mad, marvellous game, the adrenalin, the profile, the career, but is it worth having their name splashed across the back-pages, their manhood and integrity questioned and family hounded for £80,000 a year?
And so the FA is investigating swiftly. It is in nobody's interests for the sport's latest racial controversy to drag on as Chelsea managed with the John Terry affair. Inevitably there will be scepticism about Chelsea's motives, suspicions the club seek to manoeuvre themselves on to a rare position on the moral high ground yet, in fairness, they must respond to any expressed grievances by their players.
For all the widespread perception of Chelsea as a club without class off the pitch, as essentially an organisation that has harried officials like Anders Frisk and Tom Henning Ovrebro into early retirements, any allegation of racism needs airing.
Chelsea's chief executive Ron Gourlay has pushed through this complaint to the Premier League and now FA.
Gourlay's credibility as a man fit to govern a leading club like Chelsea sustained a pummelling during the cackhanded handling of the Terry-Ferdinand saga. The latest edition of the fanzine cfcuk carries a picture of Gourlay on the cover with the words: "(Sorry but) You don't know what you're doing." If only the true-blue, warm-hearted, right-minded spirit of Matthew Harding continued to suffuse Chelsea they would have stronger leadership.
Gourlay could be right. Clattenburg may have a case to answer, although the word among referees was that he was being unfairly maligned. Clattenburg had a terrible game at the Bridge but that does not mean he was either dishonest or racist. (© Daily Telegraph, London)