Protestors lined the streets Saturday afternoon, disagreeing with the Governor's decision.
"I am a mother and my son got killed in 2001 and I'm just out here to stand out here for justice for the other mothers, for that mother," said Yvette Harris, a woman walking with the crowd.
The curfew comes after some looters targeted neighborhood businesses early Saturday morning.
"Last night, after hours of peaceful protesting, small groups took to the streets with the intent of committing crimes and endangering citizens," Nixon said. "That is unacceptable."
During the press conference, Nixon was interrupted several times by members of the community calling for an indictment against Officer Darren Wilson who shot and killed Brown.
The man in charge of security for the city, Missouri State Highway Patrol Captain Ron Johnson, says the investigation is speeding up with 40 FBI agents arriving in Ferguson this morning.
"What we're doing now is not who we are," said Johnson. "Yelling at each other is not going to solve that. We're all talking about the same concerns, the same passion."
Nixon will decide Sunday whether or not to lift the state of emergency.
He says it all depends on how crowds react to the 12 a.m. curfew on Saturday.