Cops are probing a complaint of racist language during the Kilmarnock v Rangers game earlier this week.
An audio clip emerged online on Thursday of a supporter allegedly directing a racist slur at Colombian forward Alfredo Morelos.
Kilmarnock vowed to take tough action against anyone who is caught shouting discriminatory insults.
Audio of the incident does appear to be inconclusive, however fans are adamant the clip is clear.
Cathy Jamieson, a director at the Ayrshire club, confirmed it was a Killie fan who came forward to say they heard racism at the game where Rangers lost 2-1 after a late winner by Eamonn Brophy.
Cops have now confirmed they are looking into the incident.
Police Scotland said in a statement: "We can confirm we are investigating a complaint of racist language being used during the Kilmarnock v Rangers match at Rugby Park on Wednesday, February 12 2020.
Enquiries are ongoing."
