Seeing as I’m not a Portuguese speaker is there anything close to “puta” that is a racial slur? Maybe in Spanish? If Holgate thought he heard something like that it could explain his reaction.But Holgate doesn't seem to lose it until the verbal altercation. Lip readers on Twitter are claiming Firmino said: CE TA LOUCO? CE TA LOUCO? FILHO DA PUTA,” which translates as: “Are you crazy? Are you crazy? Son of a bitch!”
http://www.empireofthekop.com/2018/01/05/what-firmino-actually-said-to-holgate-despite-racist-allegation/
The Echo has a good outline on the procedure the FA follows in cases like this.
http://www.liverpoolecho.co.uk/sport/football/football-news/roberto-firmino-mason-holgate--14120511
Given that outlined procedure I can't see how Firmino would be facing any punishment in the event of conflicting statements.
The other thing to consider is that Liverpool players have been subjected to racist abuse this year - so I imagine the Club will be pressing Firmino to own up to it if he did, indeed racially abuse Holgate.
Still don't understand why it wasn't a yellow card on Holgate in the first place.