Stewart was targeted on social media after being sent off as Aberdeen lost 3-1 to St Mirren in the cinch Premiership on Saturday. The Dons were leading 1-0 when Stewart hauled back Jonah Ayunga and Mark O’Hara’s resulting penalty turned the game in St Mirren’s favour.
Highlighting the offending post, Stewart stated: "There is many highs and lows in this beautiful game and I take full responsibility for my mistake, which cost us three points. But I will not take racist abuse lightly.”
Aberdeen followed with a statement supporting their player on Tuesday evening which read: “We strongly condemn all forms of discrimination and are shocked at the racist abuse aimed at our captain, Anthony Stewart.
“Anthony has our full support and as a club we are currently undertaking a stringent internal investigation to try to identify the person responsible.
“Aberdeen FC stands free from all forms of discrimination, and we will simply not tolerate this type of abuse.”
Englishman Stewart – who is suspended for Wednesday night’s league visit to Kilmarnock – was installed as Aberdeen skipper by boss Jim Goodwin after signing from Wycombe Wanderers in the summer.