ST. LOUIS - The white officer who shot dead unarmed black teenager Michael Brown in August, spurring a wave of violent protests, would be the first policeman charged for killing a suspect in St. Louis County in more than two decades.
For weeks, protesters in the mostly black St. Louis suburb of Ferguson have piled pressure on authorities, demanding that the officer, Darren Wilson, be charged and Prosecutor Bob McCulloch be replaced with a special prosecutor.
The prosecutor opted not to press charges and presented the case to the grand jury because of conflicting testimony from witnesses, his office said.
"It's not even a question about whether there will be unrest, people have made it very clear. We have a very fragile peace right now. If people don't feel like they get justice, it will be very hard to hold these folks back," said St. Louis Alderman Antonio French.
The embattled McCullough, whose office has prosecuted more than 700 murder cases since 1991, has overseen 33 prosecutions of police officers during his 23-year term but has never pressed charges against an officer accused of killing a suspect.
His spokesman, Edward Magee, said prosecutors review several police shootings each year but rarely pursue charges, largely because laws give police a broad latitude to defend themselves and use deadly force if they believe they are in imminent danger.
McCulloch's office said there were four cases of police shootings he has brought to a grand jury. None resulted in criminal charges, including a much publicized 2000 case of two law enforcement officers who shot and killed two unarmed black men during a drug bust.
In a process much different from a trial, a grand jury is guided by the prosecutor, who determines what evidence to present and instructs members on what charges may apply.
The prosecutor's office is asking for patience as forensics and autopsy evidence are presented to the grand jury, which is meeting four to eight hours each Wednesday. Witness testimony is still being gathered, Magee said.
Two attorneys at the prosecutor's office, Kathi Alizadeh and Sheila Whirley, are presenting the evidence to the grand jury, Magee said. Alizadeh, with 26 years on the job, including 22 murder cases, is leading the presentation.
"People just need to wait," Magee said. "People are still coming forward and we are still waiting for the investigation to be completed."
In the 33 cases prosecuted by McCulloch's office, police officers were charged with a range of crimes that included allegations of rape, assault and murder. In most of those cases, McCulloch's office leveled charges directly and did not take the cases to a grand jury.
Charges are brought directly when there is a "clear-cut probable cause," Magee said. adding that there is no such clarity in the Brown shooting.
Accounts of the altercation between Wilson and Brown differ. Some witnesses have said Brown posed no threat to the officer and had his hands raised in surrender when he was shot, while friends of the officer have said Brown injured Wilson before the shooting. An autopsy showed the teenager was shot at least six times, including twice in the head.
In an unusual provision, the prosecutor's office has pledged that all the evidence at some point will be turned over to the public to help address questions about the case, even if no charges are brought, Magee said.
Ferguson Mayor James Knowles said officials have been meeting to prepare contingency plans in case new protests erupt if charges are not pressed.
"It is being planned for. I don't know where it will explode. There will be civil unrest far beyond Ferguson," Knowles said in an interview with Reuters. "The St. Louis region is preparing for that."
Protests have been persistent but less violent in recent weeks - until Wednesday, when about three dozen protesters were arrested after demonstrators tried to block a US highway through St. Louis and clashed with police.
The night before, many residents at a packed Ferguson city council meeting told city leaders there would be no peace until Wilson, who protesters called the 'killer cop' - is arrested and jailed.