Ferguson police officer Darren Wilson shot and killed the teen on August 9th.
The grand jury, which replaces the preliminary hearing, is another method by which criminal charges can be filed. The grand jury is tasked with examining evidence presented by St. Louis Prosecuting Attorney Robert McCulloch and to determine whether Wilson will be charged.
The fate of Ferguson officer Darren Wilson, who shot and killed Michael Brown, is now in the hands of a grand jury.
"Anything that's somewhat complicated that would require several witnesses, we usually we take those cases to a grand jury," said Edward Magee, Executive Assistant For St. Louis Prosecutor's Office.
That grand jury consists of 12 St. Louis county residents-- nine who are white, three who are African Americans, seven of whom are male and five of whom are female.
Magee said the prosecution team will present evidence to the grand jury in closed proceedings.
"We will present everything that's available to us," said Magee.
Jurors will then be tasked with determining if there is probable cause to bring a charge-- nine votes of "true bill" would result in an indictment-- meaning Wilson would be charged and a criminal case would be initiated.
"They will be explained the possible charges which could range from anywhere from murder in the first degree down to involuntary manslaughter," said Magee.
Greene County Prosecuting Attorney Dan Patterson said grand juries can strengthen a prosecutor's case.
"A grand jury in general can be very helpful because in addition to hearing the testimony, grand jurors also get ask questions, and so it's a more intense way to investigate and charge a case then simply reading the allegations on paper," said Patterson.
But lawyer Tom Carver said grand juries rarely help defense teams.
"Lawyers for defendants are not permitted in the grand jury proceedings which means that some think that only one side of the case gets presented and that's the prosecutor's side," said Carver.
Magee says St. Louis County has prosecuted officers in the past, but that this case is unique.
"This is a complicated case not just because it's a law enforcement officer, but it will probably involve claim of self-defense, and that's what makes it complicated," said Magee.
Now if Wilson is not indicted, the case won't move forward. But if he is, Wilson would have to surrender or be issued a warrant for his arrest.
Magee said since the investigation is on-going, the process for the grand jury could take weeks, and possibly months.
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