(CNN) -- They took to the streets, to radio call-in shows, to social media to vent their frustration. George Zimmerman not guilty? It can't be, they said.
"Only white life is protected in America," one protester in Washington shouted Sunday, a day after a Florida jury found the Hispanic former neighborhood watch volunteer not guilty of second-degree murder in the 2012 death of African-American teenager Trayvon Martin.
But, as with all things surrounding the divisive case, not everyone shared the view that Martin was the victim, that the verdict was wrong.
While few, if any, Zimmerman supporters held rallies celebrating the verdict, on the "George Zimmerman is Innocent" Facebook page, fans were hawking T-shirts and stickers hailing Zimmerman and posting messages of encouragement.
"Thank God the jury got it right and found George not guilty," Facebook user Pete Habel posted Monday on the page.
Sunday's protests against the verdict were largely peaceful.
In Washington, protesters chanted "No justice, no peace" and "Trayvon was murdered" as they marched, freelance photographer Michael Kandel told CNN's iReport.
In New York, demonstrators marched across Manhattan and filled Times Square.
"This is what democracy looks like," they chanted.
And just steps away from the courthouse where a jury acquitted Zimmerman, Sanford, Florida, demonstrators vowed that their fight wasn't over.
"Nationwide protest to demand justice," protesters chanted.
In Los Angeles, a demonstration against the verdict grew tense late Sunday and early Monday.
Some protesters hurled flashlight batteries, rocks and chunks of concrete toward police, Los Angeles police spokesman Andrew Smith said. Police responded by shooting bean bags at protesters. Police arrested at least nine people, Smith said.
On Monday, protesters were expected to gather at noon in Cleveland with bags of Skittles -- the candy that Martin had just purchased when he was killed, CNN affiliate WEWS reported.
The Rev. Jesse Jackson called for protests to continue, but to remain peaceful.
"There will be protests, but they must be carried out with dignity and discipline," he told CNN's "New Day."
"What will happen if there, in fact, are riots, it gives sympathy to Zimmerman, and discredits Trayvon. Trayvon deserves sympathy. Zimmerman and his school of thought does not."
Many of the protests, including those in New York and Los Angeles, drew demonstrators from a wide variety of races. But many expressed the same belief: that Martin's death was spurred by racial profiling and that Zimmerman's acquittal was unjust.
Protesters demanded that the government investigate further, Kandel said.
"They believe that this is a civil rights issue that must become the topic of a national conversation in the coming days," he said. "They did not believe justice had been served."
The attorney for Martin's family, Benjamin Crump, renewed his call Monday for such an investigation. He said Zimmerman racially profiled Martin because he superficially resembled African-American youths who had been arrested for recent burglaries in his neighborhood.
"That's profiling," Crump told CNN's "New Day." "And there's a big question whether that's allowed, and so I think the Justice Department should look at that."
The other side
Conversely, Zimmerman supporters -- speaking mostly through social media channels -- argued that the jury's verdict was correct.
"If Zimmerman was black, would people act the way they they're acting now? The facts found him innocent, the 'people' are the racist ones," Facebook user Ben Biller posted on the "George Zimmerman is Innocent" page.
On Twitter, user ElDonJuanDiaz posted: "George Zimmerman is a national hero. To you liberals and black people who believe everyone is racist keep crying."
Zimmerman's friend and former next-door neighbor, Jorge Rodriguez, said he always expected an acquittal.
"This is so far from being racial, it's not even funny," he told CNN's Chris Cuomo on "New Day."
"Just because he has a white last name and an African-American was dead, automatically everybody assumes racial. This is far from being race. This is just a bad situation that happened."
Tony Johnson, who is black, said he was disturbed by the "outbursts from people who didn't know the facts of the case, yet (were) still screaming about an injustice."
"I'm actually glad the verdict was not guilty," he told CNN's iReport. "Only based on the evidence that was presented in court, it screams self-defense.
"This wasn't about race," Johnson continued. "It was about a man's rights to defend himself. It's not a crime to follow anybody; therefore, the fact that they got into an altercation and George Zimmerman was forced to use deadly force, it's not a crime. Our Constitution states that."
Mark O'Mara, Zimmerman's defense attorney, said he was surprised by some of the protest.
"I'm a bit surprised that there is outrage because we had hoped that everybody would look at this case as being a very fair trial where both parties were represented well," he said.
Pushing for peace
President Barack Obama called for peace Sunday and acknowledged the Zimmerman case has stirred strong emotions.
"I now ask every American to respect the call for calm reflection from two parents who lost their young son. And as we do, we should ask ourselves if we're doing all we can to widen the circle of compassion and understanding in our own communities," he said.
"We should ask ourselves if we're doing all we can to stem the tide of gun violence that claims too many lives across this country on a daily basis," Obama said.
One critic of the verdict, Terri Weems, said the trial was a referendum on race that confirmed what she said Martin supporters knew all along.
"That's our society," she said as she headed into church in Washington on Sunday. "We expected not to be given justice. We haven't been dealt justice all this time. ... It's very disheartening."
NAACP President Benjamin Jealous told CNN's "State of the Union" on Sunday that the largely peaceful protests were a positive sign.
"I think we should, frankly, right now be celebrating the fact that we've seen a generation of young people respond by using our system, raising their voices, but not using their fists," he said.