By Barbara Liston and Steve Gorman
ORLANDO, Fla./LOS ANGELES (Reuters) - Attorney General Eric Holder renewed hints the federal government may pick up where Florida authorities failed in their prosecution of George Zimmerman, as demonstrators continued to protest his acquittal in the shooting death of Trayvon Martin.
Zimmerman, 29, remained in hiding on Tuesday after a jury of six anonymous women on Saturday found him not guilty of second-degree murder and manslaughter, ending a Florida state prosecution of a case that has captivated and polarized the U.S. public on issues of race, gun and self-defense laws.
The shooting in the central Florida town of Sanford on February 26, 2012, prompted street demonstrations last year when police initially declined to arrest Zimmerman, and the verdict triggered a new wave of marches from critics saying Zimmerman racially profiled Martin as a criminal.
Zimmerman's defense lawyers complained race was wrongly injected into the case and that Zimmerman acted in self-defense, accusing civil rights leaders of inflaming racial passions with their calls for a federal investigation of Zimmerman on civil rights grounds.
In California, police and civic leaders braced for unrest while appealing for calm on Tuesday after nearly two dozen protesters in Los Angeles and Oakland were arrested during a second night of civil disturbances sparked by the not guilty verdict.
Police in Los Angeles said the lawlessness was committed by about 150 people who broke off from an otherwise peaceful prayer vigil held in memory of Martin. In Oakland, about 250 protesters swarmed downtown streets on Monday night, vandalizing cars and businesses and scrawling graffiti. Nine were arrested.
One of the six jurors, B-37, told CNN on Monday she did not think Zimmerman racially profiled Martin and believed Martin attacked Zimmerman first. The entire panel - five white women and one Hispanic woman - believed race played no role in the case, she said.
Juror B-37's interview with CNN, her faced blacked out in silhouette, prompted extreme reactions including death threats on social media.
Holder, the chief U.S. prosecutor and an appointee of President Barack Obama, told the annual convention of the National Association for the Advancement of Colored People in Orlando on Tuesday that his office would continue its investigation of the case, which could possibly lead to federal charges against Zimmerman.
"I," he said with emphasis, "am concerned about this case."
Holder called for a review of self-defense laws like the one in Florida that appeared to play a role in his acquittal. According to the jury's instructions, Zimmerman had "no duty to retreat and had the right to stand his ground and meet force with force" if he reasonably feared for his life or great bodily harm.
Holder, who is black, also related personal stories about being racially profiled as a young adult and stopped by police.
"Trayvon's death last spring caused me to sit down and have a conversation with my own 15-year-old son, like my dad did with me," Holder said. "This was a father-son tradition I hoped would not need to be handed down."
MORE PROTESTS PLANNED
Civil rights leader Al Sharpton called a "Justice for Trayvon Day," planning a further 100 demonstrations in 100 cities on Saturday.
"People from all over the country will gather to show that we are not having a two- or three-day anger fit. This is a social movement for justice," Sharpton told reporters in Washington.
The case has also provoked reactions from celebrities such as R&B legend Stevie Wonder, who said on Sunday that in the future he would not perform in Florida and the other states with "Stand Your Ground" self-defense laws until the laws were repealed.
While Zimmerman's defense opted against a Stand Your Ground defense, it relied on the self-defense statutes and the language in the jury instructions
"I decided today that until the Stand Your Ground law is abolished in Florida, I will never perform there again," Wonder said to cheers at a performance in Quebec City. "As a matter of fact wherever I find that law exists, I will not perform in that state or in that part of the world."
(Writing by Daniel Trotta; Editing by Steve Orlofsky)