Two people have been arrested for allegedly directing racial abuse at Motherwell substitute Christian Mbulu during his side’s defeat at Hearts.
Police Scotland have been given footage which shows around 20 fans in the main stand at Tynecastle shouting comments at the 22-year-old as he warmed up.
Hearts told BBC Scotland they are “aware” of the incident and are “cooperating fully” with the police.
Motherwell boss Stephen Robinson said the act was “an absolute disgrace”.
Speaking to BBC Scotland, he added: “I’ve just seen the video of it. I thought this was 2018 but that was the dark ages and dinosaur stuff. For a player to have to take that kind of stuff is disgusting.
“They should not be anywhere near football. There is no place for that in any walk of life. No walk of life should accept that in modern society.”
Hearts’ statement added that the club “abhors racism and all forms of abuse, and the individuals in question will receive indefinite bans from Tynecastle Park”.