BALTIMORE -- Chants of "no justice, no peace, no racist police" were already echoing through the streets of Baltimore Saturday even before the start of a march that organizers billed as a "victory rally" after a prosecutor filed criminal charges against six officers involved in the arrest of a man who died in police custody.

State's Attorney Marilyn Mosby on Friday charged the six with felonies ranging from assault to murder in the death of Freddie Gray. He died from spinal injuries a week after his April 12 arrest. It provoked riots on the streets of West Baltimore and quickly became a rallying cry against police brutality and social inequality in the city.

The march Saturday was supposed to be a mass protest of Gray's custody death, but after Mosby's announcement, the tone had changed to more celebratory.

Shortly after noon at Gilmor Homes, a group of demonstrators gathered to march, both black and white. There were grown-ups, kids and a dog.

"Are you ready to march for justice?" Kwame Rose, 20, of Baltimore, said. The crowded chanted, "Yes."

"Are you all ready to march for peace?" Rose asked. "Yeah," the group answered.

Near a CVS store that was looted and burned earlier in the week, groups of policemen stood on corners and a police helicopter flew overhead. Some officers twirled wooden batons idly. Someone had used chalk to draw a peace sign and write "Freddie Gray" on the brick face of the store. Hearts and dollar signs had been drawn on the store's boarded up windows.

Chrystal Miller, 47, and Linda Moore, 63, planned to join the march. Both said they had obligations during the week and this was the first time they'd been able to participate. Moore brought a sign that said "The Dream Still Lives," a reference to the Rev. Martin Luther King's "I Have a Dream" civil rights speech.

Black Lawyers for Justice is expecting at least 10,000 people to show up downtown.

Miller, who was pushing her 1-year-old son in a stroller, said she hoped the march would be peaceful. And Moore said she believed it would be because of the charges.

Still, Miller said the story isn't over.

"It's going to be a long road," she said, adding that the officers still need to go to court and she wasn't sure they'd wind up with jail time as she hoped. "Nothing is going to happen overnight."

Mosby said that after reviewing the results of a police investigation turned over to her just one day before, she had concluded Gray's arrest was illegal and unjustified. She said his neck was broken because he was handcuffed, shackled and placed head-first into a police van, where his pleas for medical attention were repeatedly ignored as he bounced around inside a small metal compartment in the vehicle.

The officers missed five opportunities to help the injured and falsely imprisoned detainee before he arrived at the police station no longer breathing, Mosby added.

The police had no reason to stop or chase after Gray, Mosby said. They falsely accused him of having an illegal switchblade when it was a legal pocketknife, and failed to strap him down with a seat belt, a direct violation of department policy, she said.

The six officers were scheduled to appear publicly in court for the first time at the end of the month. A lawyer hired by the police union insisted the officers did nothing wrong. Michael Davey said Mosby has committed "an egregious rush to judgment."

Gray's stepfather, Robert Shipley, said the family was happy the officers were charged, and he reiterated a plea to keep all public demonstrations peaceful.

"We are satisfied with today's charges; they are an important step in getting justice for Freddie," Shipley said. "But if you are not coming in peace, please don't come at all."

The family lawyer, Billy Murphy, said the charges are "a first step but not the last," adding that Baltimore now has an opportunity to set an example for cities across the nation grappling with police brutality.

"The people of Philadelphia, New York, Cincinnati, and in numerous cities and towns are expressing their outrage that there are too many Freddie Grays," Murphy said. "If Freddie Gray is not to die in vain, we must seize this opportunity to reform police departments throughout this country."

Others saw Gray's arrest and death as a reflection of Baltimore's broad social and economic problems and the announcement of charges prompted celebrations in the streets.

At City Hall, Andrea Otom, 41, sobbed with something like joy.

"You have to be able to expect that at some time, the pendulum will swing in your favour, and in the black community we've seen it over and over and over where it doesn't," Otom said. "I'm so happy to see a day where the pendulum has finally begun to swing."