Steelmen boss Stephen Robinson called the vile abuse "absolutely disgusting" in a scathing interview following the game.
Mbulu was reportedly subjected to vile taunts by around 20 Hearts fans in the pre-match warm-up at Tynecastle this afternoon.
Speaking after the game – a 1-0 win for Hearts – Robinson said: "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 absolutely 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 themselves released a statement slamming the actions of the fans in question – threatening them with lifetime bans.
They claimed the club "abhors racism and all forms of abuse, and the individuals in question will receive indefinite bans from Tynecastle Park".
Hearts moved up to fourth in the Scottish Premiership after the win, with Motherwell down in ninth.
Source: Read Full Article