The university has suspended Rettke, and issued a statement saying his actions "go against the values of our university where people come first and all are treated with dignity and respect."

University President Brian Noland said: "I was offended, but I was also saddened. The nation is not only raw, but it's healing.

"We are exceptionally proud of the students who were peacefully participating in the event and the manner in which they exercised restraint, thoughtfulness and strength in the face of inappropriate and offensive behaviour."