It's interesting how many posters in this thread are dismissing out of hand the possibility that Firmino could be guilty. Even going as far to say that Holgate has fabricated the entire story to avoid a booking. Or laughably assuming that because their skin tone is vaguely similar, they couldn't possibly racially abuse each other. And all this based on very limited footage, in which Firmino is facing away from the camera at the vital moment. People have said that they can lip read what was said, but I have to assume that they are referring to the words Firmino shouted has he ran towards Holgate, when his mouth was visible to camera. Which clearly didn't bother Holgate, because he didn't become incensed until later in the exchange, at which point Firmino was still talking but no longer facing the camera. I have yet to see any footage which conclusively covers the moment that the alleged language was used.
Now, I would like to think that Firmino is innocent as much as anyone, but as we should all be well aware - footballers are mostly bellends, irrespective of who they play for. We shouldn't let club politics cloud our judgement here. If Firmino is guilty, then he should be punished. And I would assume that anybody opposed to racism would have more interest in the truth than on minimising a potential ban for our player.
Do I have any confidence that the FA will carry out the investigation competently (or indeed fairly)? No. In fact, I think there's every chance that the investigation will be prejudiced against the non-white foreigner, being as it is a corrupt organisation run largely by white men. But it might be worth waiting a little while to see whether any more concrete information emerges before excusing the dismissing the accusation and going all out to discredit the (alleged) victim. Because however unlikely it may seem, if it emerges that Firmino did use racist language, then some contributors here might end up feeling a little embarrassed, if not a little ashamed.
If he used the "n words" - negro or negrito - then I'm going to burn my "Bobby Is Innocent" T-shirt in front of a cross. Which will also be burning, because of all the bad racists in Liverpool.