The pair came together after Arsenal won a penalty, which was duly scored by Bukayo Saka. There was a lengthy confrontation between Gabriel and Henderson before team-mates on both sides got involved.
Both Gabriel and Henderson were spoken to post-match by Oliver for their observations. It remains unclear exactly what was said in the bust-up with no public comment from either club.
It is thought the FA have been seeking eyewitness accounts on the fracas, with Oliver speaking to both players and also both managers before issuing his report to the governing body. The FA are also thought to have brought in a lip-reader to analyse video footage.
All parties are co-operating with the FA and will follow disciplinary procedures as the body mull over pursuing further action. Since Sunday, fresh footage has emerged on social media of Henderson and Gabriel sharing a feisty handshake.
The players spoke one-to-one with the Brazilian defender’s countryman Roberto Firmino stood next to them and Klopp also keeping a keen eye on the heated discussions.