A grand jury is considering evidence to determine whether Officer Darren Wilson should be charged in the fatal shooting of Michael Brown in Ferguson, Missouri, on Aug. 9.
St. Louis County prosecutor Bob McCulloch says it will be several weeks before a decision is made. Here is a look at how grand juries work in Missouri:
Q: How many people are on the grand jury and how are they selected?
A: A grand jury is made up of 12 people who "shall be selected at random from a fair cross-section of the citizens" of St. Louis County, according to Missouri law. The grand jury in the Brown case is 75 percent white: six white men, three white women, two black women and one black man. The county is 70 percent white. Brown was black while the officer is white.
Unlike a trial, where lawyers can object to having certain people on a jury, there is no role for objections inside a grand jury, said Susan McGraugh, a professor at St. Louis University law school.
Q: What happens in a Missouri grand jury?
A: Prosecutors present evidence and summon witnesses to testify. A grand jury is a powerful tool for investigating crimes because witnesses must testify unless they invoke a constitutional right to remain silent, McGraugh said.
"If they refuse, they can be jailed," she said.
The use of grand juries varies greatly by state; it's the only way to return an indictment in federal court.
Q: Who is inside the room?
A: The jury, a prosecutor and a witness. No one else is present unless a witness claims a constitutional right against testifying and needs a lawyer, McGraugh said.
"The proceeding is closed to everyone," she said.
Q: Do charges require a unanimous vote?
A: No. Consent from nine jurors is enough to file a charge in Missouri. The jury also could choose to file lesser charges or no charges.
The jury is "not bound by the recommendation of the prosecuting attorney," McGraugh said.
The Brown family's attorney, Benjamin Crump, said the panel "works perfectly" as long as the prosecutor presents the necessary evidence and doesn't withhold any.
Q: Can jurors speak to the public?
A: No. Disclosing evidence, a name of a witness or an indictment can lead to a misdemeanor charge.
Q: Do jurors take an oath?
A: Yes. It's lengthy and very formal.
The oath, in part, says: "Do you solemnly swear you will diligently inquire and true presentment make, according to your charge, of all offenses against the laws of the state committed or triable in this county of which you have or can obtain legal evidence?"