The acquittal of George Zimmerman in the shooting death of an unarmed black teenager in Florida last year – a case that riveted the United States – has intensified that country's debate over race and has set off calls for the federal government to press civil-rights charges.
President Barack Obama, in a statement Sunday, called the death of 17-year-old Trayvon Martin a tragedy – "not just for his family, or for any one community, but for America." He urged calm in the wake of the verdict, asking Americans to honour the victim by determining "as individuals and as a society, how we can prevent future tragedies like this."
As black parents voiced fears for their sons at emotional rallies nationwide, the National Association for the Advancement of Colored People called for federal civil-rights charges against Mr. Zimmerman, saying there is reason to believe it was a racially motivated crime.
The Department of Justice, which opened its own probe into Mr. Martin's death last year, issued a statement saying it was continuing to evaluate "whether the evidence reveals a prosecutable violation." Mr. Martin's family is also considering bringing a wrongful death civil suit.
Mr. Zimmerman, who is white and Hispanic, encountered Mr. Martin in February last year in a gated neighbourhood in Sanford, Fla. What happened that night remains unclear, but at some point the two tussled and Mr. Zimmerman shot and killed the teenager. The country had watched much of the court proceedings live on television over two weeks, with celebrities and other national figures weighing in on whether racial profiling provoked the shooting or whether it was an act of self defence.
At a protest in New York's Union Square, one of several sombre, peaceful events across the country on Sunday, hundreds of people chanted "No justice, no peace," and wore black-and-grey stickers with the words, "We are all Trayvon."
Sharon Johnson, a 50-year-old social worker, was among them. She said she had never attended a protest before, but "until you've been there, you'll never understand. Until you experience what it's like to have your son call you and say, 'Mom, I was just pulled over and there are 10 cops surrounding us.' And you say, 'Stay on the phone so I can hear you, I'm on my way.'"
Mr. Zimmerman's lawyers said he was attacked by Mr. Martin. Civil rights activists say Mr. Martin was followed simply because he was young, black and male, leading to the confrontation that ended in his death. The six jurors, all women, heard conflicting testimony about who was the aggressor, and had to weigh that against the provisions of Florida's controversial Stand Your Ground law that gives people scope to use deadly force if they fear they are in deadly or grave danger.
They acquitted Mr. Zimmerman, a 29-year-old former neighborhood-watch volunteer, on Saturday, the second day of their deliberations. He had faced a second-degree murder charge, which carries a maximum sentence of life in prison, and the lesser charge of manslaughter, which carries a maximum 30-year sentence.
Mr. Martin had been visiting his father, who lived in the gated neighbourhood, the night he was killed. He had gone out to buy snacks when Mr. Zimmerman spotted him and called 911 to report seeing a "suspicious person" in the area. There were no witnesses to the shooting. But from the start, it was the subject of widespread outrage, with some calling Mr. Zimmerman a hero protecting his neighbourhood and others attacking him as a gun-slinging vigilante.
Sanford police, for instance, did not immediately charge Mr. Zimmerman after the shooting, citing the Stand Your Ground laws and his assertion he was attacked by Mr. Martin. Charges were brought after a special prosecutor was named in response to protests and demands from Mr. Martin's family that Mr. Zimmerman be brought to court.
At a small rally in Denver, Shareef Aleem stood before a crowd of about 100 people at the foot of a statue of Martin Luther King Jr. in central City Park. Protesters wore hooded sweat shirts similar to the one Mr. Martin was wearing when he was shot, and T-shirts with the slogan: "It's not a black or white thing. It's a right or wrong thing."
By the time he finished speaking to a mixed crowd of blacks and whites, his face was stained with tears. "We need more from you," he said, addressing the whites in the audience. "We need you to go back to your community and tell people what you saw today. If you really stand with us, you need to go back and challenge your family and friends about white supremacy and white privilege."
Mr. Aleem is a leader in a Denver organization that distributes cards with phone numbers for the American Civil Liberties Union, information about constitutional rights, and advice to young black men to remain calm if they are stopped and questioned by police.
"Be assertive, but not angry," Mr. Aleem said in an interview. His mother gave him similar advice when he was young. "It's not easy, but with a little bit of patience and practice, you can do it." Now he is the father of three teen-age boys, and said he tells them "to be aware every time they leave the house that they might not come back."
Tonja White Mathews, a lawyer in Florida, said Sunday she had followed the case closely, both "from a parental standpoint and a legal standpoint." Ms. White Mathews, who is black, said she has often counselled her teenaged son about how to behave should he be stopped by police – to speak clearly, to avoid sudden moves. After hearing the verdict Mr. Martin's death, she said, she thought: "Okay, well, what do we say now? Now we have to worry about any John Doe who thinks we're suspicious."
With a report from Joanna Slater in New York.