The U.S. Department of Justice has mounted an unusually swift and aggressive response to the death of Michael Brown, from an independent autopsy to dozens of FBI agents combing Ferguson, Missouri, for witnesses to the shooting of the unarmed black 18-year-old by a white police officer.
The goal, legal observers say, is to ensure that the truth about the killing is revealed, to ease racial tensions, and to reassure those fearing a cover-up that justice will be done.
Brown was shot dead in the street in the St. Louis suburb on Aug. 9. Gov. Jay Nixon asked for a federal investigation two days later, after riots erupted when the county police force confronted protesters with armored vehicles, tear gas and dogs.
After the images of the military-style police response drew widespread criticism, federal officials said they were coaching local authorities on different tactics.
On Saturday, 40 FBI agents started going door-to-door in the neighborhood where the shooting took place, interviewing witnesses and gathering information. An independent federal autopsy was announced Sunday, and President Barack Obama announced Monday that Attorney General Eric Holder would travel to Ferguson to meet with investigators and community leaders.
"What they usually do is wait for the local investigation to complete itself," said Alberto Gonzales, former attorney general under President George W. Bush.
Gonzales said that although he did not have all the information being evaluated by federal officials, it appeared to be an aggressive and unusual response to an unusual case.
"They're going in with one goal: to ascertain the truth. And to do so in a way that raw feelings can be comforted and soothed," said Gonzales, who is now dean of the Belmont College of Law in Nashville.
Ferguson is about 70 percent black. Ferguson's mayor is white, as are five of six city council members and 50 of its 53 police officers. Many in Ferguson and beyond fear that local officials will not act fairly in determining whether to charge the officer, Darren Wilson, with a crime.
St. Louis County Prosecuting Attorney Bob McCulloch, who is in charge of the investigation, also is white.
He comes from a family of police officers, including his father. When he was 12, his father was fatally shot by a black man while responding to a call. In 2001, McCulloch brought no charges against two officers who fired 21 shots into a vehicle, killing two black men during an attempted drug arrest.
McCulloch has declined calls to step away from the case, saying in a television interview, "I've been as fair and impartial and done as thorough of a job as we could."
At the Department of Justice, Holder, the first black attorney general, who took office promising to fiercely fight discrimination and inequality, has been an increasingly visible presence during the Ferguson case.