The Belgian forward was the recipient of vile racist abuse before, during and after scoring a 95th-minute penalty to equalise in the first leg of Inter's Coppa Italia semi-final tie against Juventus.
Lukaku made a "shut it" gesture after scoring, a celebration he also used throughout the international break. Despite being on the receiving end of alleged monkey chants and gestures, the referee gave the Inter man a second yellow card for antagonising the crowd.
In the wake of Tuesday's events, Juventus have clarified that they will aid the authorities to find the perpetrators inside the Allianz Stadium.
A statement read on the club's Twitter: "Juventus Football Club, as always, are collaborating with the police to identify those responsible for the racist gestures and chants which took place last night. The Codice di Gradimento will be applied to those responsible."
This added to Inter's denouncement of the racist acts, as they said in a statement earlier on Wednesday: "We are brothers and sisters of the world. Since 9 March 1908, this has been our story. We want to firmly reiterate that we stand united against racism and all forms of discrimination."
Meanwhile, Lukaku's agency Roc Nation has publicly condemned the referee's decision to dismiss the player, and called on the authorities and both clubs to do more to protect players from racism.
Lukaku is the latest in a plethora of black players that have been targeted by Italian fans, with Lecce's Samuel Umtiti similarly abused back in January.