In a Snapchat video shot during the Europa League quarter-final clash at the Emirates, the culprit can be heard using the ‘n-word’ to refer to Koulibaly – with the word also written across the screen for part of the 15-second recording.
The Gunners beat the Italian club 2-0, but much like Chelsea’s victory over Slavia Prague, the result has been marred by racism.
On the same night, Blues fans filmed themselves chanting ‘Salah is a bomber’ in a Czech pub.