A press conference to announce a curfew in Ferguson quickly turned into a shouting match as frustrated protesters voiced their anger that a week after Michael Brown was shot and killed, so many questions remain unanswered.

Missouri Gov. Jay Nixon, a Democrat, announced that he had declared a state of emergency and was implementing a curfew between midnight and 5 a.m. He said the intention was to find a balance between First Amendment rights and the community’s safety.

“… we cannot allow the ill will of the few to undermine the goodwill of the many, while putting the people and businesses of this community in danger,” Nixon said.

He said the “eyes of the world” were watching Ferguson, and that justice would only prevail if there was peace. “In the morning, this community will rise with the sun to renew its quest for justice.”

But after his opening remarks, Nixon quickly lost control of the crowd.

Someone yelled from the crowd, “You need to charge that police with murder.” Others demanded to know how the curfew would be enforced. “Gonna do tear gas again?” one person asked.

“The best way for us to get peace is for everybody to help to make sure everyone gets home safe tonight and gets a good five hours sleep tonight,” Nixon began, as someone yelled, “We don’t need sleep. We need justice!”

Nixon did not say how long the state of emergency would last. Capt. Ronald S. Johnson, the State Highway Patrol commander who took over security in Ferguson on Thursday, said the curfews would be enforced through communication, not physical force.

“We will be telling people, ‘It’s time to go home,’ ” he said.

Johnson also said FBI agents were advancing its investigation in the neighborhoods and interviewing witnesses. He said they were passing out cards to encourage people to report what they know.

The new curfew comes in response to renewed tensions Friday night and into Saturday morning. Some protesters, whose anger was reignited by the naming of the police officer who killed Brown, rioted and ransacked area businesses.