Wallace is the only Black driver in the sport’s top circuit.
NASCAR launched its own investigation following the discovery but contacted the FBI to expand the search for who committed the act.
"We don't have a lot of answers at this moment," NASCAR president Steve Phelps said on a conference call Monday afternoon.
"We're going to use every effort we can to determine who has done this. All the resources to NASCAR, the FBI, the teams of all the drivers and anyone who has any access to this said they will help figure out who has done this vile act."
"Obviously we will review the entire list with the FBI about who had access at that particular time," Phelps said. "We will look at who was in that particular area and we will be able to narrow that down. …
“Security is very tight getting in and out of the footprint."
Phelps also rejected the idea of NASCAR or Wallace staging the incident.
"I can't speak for those on social media, but I would say that is something that personally offends me," Phelps said. "This is a terrible, terrible act that has happened and for those who would think that this is staged, I don't even know where to go with that, frankly."
He added that when the person or persons responsible is found, they will "unequivocally" be banned from NASCAR for life.
"There is no room for this at all, and we won't tolerate it," Phelps said. "They won't be here. I don't care who they are, they will not be here."
NASCAR legend Richard Petty, the owner of Wallace’s No. 43 car, will attend The race for the first time this season. “There's absolutely no place in our sport or society for racism,” Petty, who is the sport’s all-time leader with 200 wins, wrote on Twitter. "This filthy act serves as a reminder of how far we still have to go to eradicate racial prejudice and it galvanizes my resolve to use the resources of Richard Petty Motorsports to create change.”