NASCAR has said its investigation did not determine who put the noose in Wallace's stall or how it got there after U.S. investigators had separately concluded that no federal crime was committed.
Wallace, the only Black driver competing in the top series, drew an outpouring of support amid the incident from fellow drivers, who afterward pushed him and his car to the start of June 22 race at the Talladega Superspeedway.
"Has @BubbaWallace apologized to all of those great NASCAR drivers & officials who came to his aid, stood by his side, & were willing to sacrifice everything for him, only to find out that the whole thing was just another HOAX? That & Flag decision has caused lowest ratings EVER!" Trump tweeted on Monday.
Although NASCAR has said that the noose was a garage door pull down, the incident took on greater significance as the nation grapples with renewed tensions over racism ahead of the Nov. 3 presidential election that has also rocked NASCAR and other sporting leagues.