Nearly all the crucial witnesses and actors in the Sean Bell shooting will testify before a grand jury in Queens over the next seven days, making this one of the most charged periods in the case since the weeks after the fatal shooting, experts, officials, and lawyers involved in the legal proceedings said yesterday.

“The next couple of weeks are going to build an expectation that justice will prevail,” a lawyer representing three eyewitnesses to the shooting, Charles King, said. “For many New Yorkers, that means that some or all of the police officers must be held criminally accountable for that evening. For others, what happened was a tragedy, but not a crime.”

In the weeks after the shooting of Bell and two of his friends by plainclothes police detectives outside a nightclub in the Jamaica section of Queens, in the early morning of November 25, 2006, parts of the city, especially Jamaica, erupted into protests and marches. Some City Council members and community leaders, such as the Reverend Al Sharpton, said the shooting was part of systematic racism in the police department, while union leaders and Mayor Bloomberg urged the city to let the legal system work its course. That time has ostensibly come, observers said.

Bell’s friends, Joseph Guzman and Trent Benefield, will appear before the grand jury on Friday morning. Between three and five of the officers involved in the shooting will appear next week, their lawyers said. More members of Bell’s party and eyewitnesses also will testify. A decision on whether to indict the officers could come as soon as the week of March 12.

“If there is no indictment, I believe there will be a very significant segment of New York City that will be traumatized by that,” a lawyer representing Guzman and Mr. Benefield, Michael Hardy, said. “Actions of people will vary, but a lot of people will be very upset. Hopefully they will express their outrage in legal ways.”

While convictions of police officers have been rare because of the nature of their interactions with city residents, indictments have occurred with more frequency. Police experts said that if any of the officers is charged with a crime, it will have a demoralizing effect on the department.

“You’ll hear the cops talking, saying things like, ‘I’m not going to do anything anymore. Why should I risk my family and my job?'” a 40-year veteran of the NYPD and former captain, Edward Mamet, said. “There’ll be a drop in arrest activity, but then a new generation, and it will go back where it was.”

Next Friday, the public safety committee of the City Council will hold a hearing about oversight of the police department, which could become a forum for more criticism.

“Whatever the outcome this week, there will be increased tensions on one side or the other,” the chairman of the committee, Peter Vallone Jr., said. “That’s why it’s important for elected officials to calm their communities.”