Liverpool won the match against Everton 2-1, but it was shrouded in controversy for an off the ball incident between Firmino and Holgate.
The Everton defender pushed Firmino by the touchline sending him flying over the advertising boards
The Liverpool forward retaliating by squaring up to Holgate with Madley getting in between the pair.
TV footage of Firmino during the exchange led to lip-reading experts claiming he said: “Es maluco, filho da puta?’ Translated that means: ‘Are you crazy, you son of a b***h?”
Holgate then reacted furiously to something Firmino seemed to say and after the game he claimed the 26-year-old had used the word “negro”.
Both players are set to be interviewed by the FA to try and get to the bottom of the incident.
But the Daily Mail claim to have seen a copy of Madley’s referee report where he stated he was unaware the Brazilian had used the racist slur.
If found guilty of using racist language, Firmino could face a huge ban much like the one Luis Suarez received for his comments to Patrice Evra in 2011.
The Uruguay international was handed an eight-match suspension by the FA, although he later disputed the punishment in his autobiography.
The report in the Mail goes on to say Holgate is also under investigation over some alleged homophobic tweets posted on his social media account in 2012 and 2013.