The reason why the federal marshalls where sent was in order to stop the violence that was being perpertuated by the mob.
He was An attorney general of the United States. He had sent the marshalls because the freedom riders were being attacked.
This was in the era of the civil rights movement. The reason the people were attacked was due to the fact that most of the attackers were pro segregation.
Read m ore on the civil rights movement here: https://brainly.com/question/131269