President Barack Obama announced Monday that Holder would pay a visit Wednesday to Ferguson, which has been rocked by clashes between protesters and law enforcement since 18-year-old Michael Brown was fatally shot by a white police officer on Aug. 9.
"This is my pledge to the people of Ferguson: Our investigation into this matter will be full, it will be fair, and it will be independent," Holder wrote in an op-ed for the St. Louis Post-Dispatch.
Holder wrote that the "full resources" of the Justice Department have been committed to the outside investigation and to calming the tensions in Ferguson. He further urged protesters to demonstrate peacefully.
"In order to begin the healing process … we must first see an end to the acts of violence in the streets of Ferguson," he wrote. "Although these acts have been committed by a very small minority — and, in many cases, by individuals from outside Ferguson — they seriously undermine, rather than advance, the cause of justice."
Protests on Tuesday night were more subdued than those of the night before. While police said most of the 47 people arrested overnight had failed to disperse, law enforcement didn't use tear gas on the smaller crowds.