FERGUSON, Mo. -- Missouri Gov. Jay Nixon said Tuesday evening he will not remove St. Louis County Prosecutor Bob McCulloch from the investigation into Michael Brown's death, a case that has sparked more than a week of angry protests and violent unrest.
A grand jury could begin hearing testimony as soon as Wednesday in the case. The 18-year-old Brown, who was black, was killed by a white police officer on Aug. 9. Witnesses have said Brown, who was unarmed, had his hands up when Officer Darren Wilson shot him multiple times.
After sundown Tuesday, the streets of Ferguson filled once more with protesters who marched along the street. There were no immediate reports of clashes with police, who stood by with batons and gas masks.
U.S. Attorney General Eric Holder is expected in Ferguson on Wednesday to oversee the federal investigation into the case.
Some black leaders have questioned whether McCulloch can investigate the case impartially. The prosecutor's father, mother, uncle and cousin all worked for St. Louis' police department, and his father was killed while responding to a call involving a black suspect.
But Nixon said removing McCulloch would only create "legal uncertainty" in a case that has already stirred emotions nationwide.
"There is a well-established process by which a prosecutor can recuse themselves from a pending investigation, and a special prosecutor be appointed," the governor said in a statement. "Departing from this established process could unnecessarily inject legal uncertainty into this matter and potentially jeopardize the prosecution."
Nixon earlier told the St. Louis Post-Dispatch that he would appoint a special prosecutor if McCulloch himself felt he should step aside.
But many observers feel that McCulloch would be biased toward the Ferguson police department and has a history of siding with law enforcement.
U.S. Rep. William Lacy Clay, St. Louis County Executive Charlie Dooley and Missouri state Sen. Jamilah Nasheed each have called on Nixon to remove McCulloch from the case.
"Given Mr. McCulloch's history and his close relationship to the Ferguson Police Department, and his track record of never indicting a police officer who used excessive, deadly force against a black suspect, it's no wonder that the community has no confidence in his independence," Clay, D-Mo., told CBS affiliate KMOV.
McCullouch has said he has no intentions of leaving the case, but would if Nixon demanded it.
Earlier Tuesday, community leaders urged Ferguson residents to stay home after dark to "allow peace to settle in" and pledged several actions to reconnect with the predominantly black population in the St. Louis suburb.
Protesters filled the streets after nightfall Monday, and officers trying to enforce tighter restrictions at times used bullhorns to order them to disperse. Police deployed noisemakers and armored vehicles to push demonstrators back. Officers fired tear gas and flash grenades.
Capt. Ron Johnson of the Missouri Highway Patrol, who is in charge of security in Ferguson, said bottles and Molotov cocktails were thrown from the crowd and that some officers had come under heavy gunfire. At least two people were shot he said, although not by police. He did not have condition updates on those who were shot. Johnson said four officers were injured by rocks or bottles.
St. Louis County spokeswoman Candace Jarret says 57 people were booked at the county jail, a number that does not include people taken to municipal jails elsewhere in the region. She did not have information on how many additional arrests were made.
Just four of the 57 arrested had Ferguson addresses. Fifty-four were cited for failure to disperse, two for unlawful use of a weapon, and one for interfering with an officer. Sixteen of those arrested were from out of state.
One peaceful demonstrator, Charles Bourrage, told CBS News correspondent Vladimir Duthiers that a small group of violent protesters were working against the message of the larger crowd.
"We grabbed those that were trying to move the violence forward and moved them back. We grabbed them literally," Bourrage said.
Benjamin Crump, an attorney for Brown's family, said the teen's funeral would be held Monday, though the time and location haven't been finalized.
Meanwhile, the start of fall classes has been postponed again in Ferguson.
Classes in the Ferguson-Florissant School District were scheduled to begin on Aug. 14, five days after Brown's death. The district initially postponed the start of school until Monday due to safety concerns, then decided to wait another full week until Aug. 25.
The nearby Jennings and Riverview Gardens school districts also canceled classes Tuesday after starting back up just days earlier.
Classes in the Normandy School District began as scheduled on Monday. Brown was a 2014 graduate of Normandy High School.