WASHINGTON (Reuters) - For all the complex issues raised by the death of Trayvon Martin, whether the U.S. Justice Department turns it into a civil rights case may depend on the relatively simple question of whether George Zimmerman was motivated by racism when he pulled the trigger.
Unless federal prosecutors can present new evidence that suggests racial malice motivated Zimmerman, who is white and Hispanic, to shoot Martin, an unarmed black teenager, they are unlikely to pursue charges, lawyers with expertise in civil rights said on Monday.
A jury in Sanford, Florida, on Saturday found Zimmerman, a 29-year-old neighbourhood watch volunteer, not guilty of second-degree murder and manslaughter in the 2012 shooting death of Martin. Defence lawyers argued Zimmerman shot 17-year-old Martin in self-defence.
State and federal courts generally have the same threshold for a criminal conviction: a finding of guilt beyond a reasonable doubt by a unanimous jury, or by a judge if a defendant waives a jury trial.
By finding Zimmerman not guilty of second-degree murder, the Seminole County jury rejected the charge that Zimmerman acted with ill will, spite or hatred.
Attorney General Eric Holder said on Monday his Justice Department had yet to decide whether to file federal civil rights charges against Zimmerman.
Like the videotaped police beating of Rodney King in 1991 or the 2006 fatal shooting of Sean Bell by New York police, the Martin case is a window into the federal government's authority to enforce civil rights.
Preachers led by Al Sharpton planned a news conference at Justice Department headquarters in Washington for Tuesday to add pressure to prosecute Zimmerman. They believe he racially profiled Martin before pursuing him with a 9mm pistol.
HATE CRIMES LAW
The law federal prosecutors would most likely use against Zimmerman was passed in 2009 to target hate crimes.
It requires that prosecutors prove that someone caused bodily injury "because of the actual or perceived race" of the victim, a bar that while straightforward can be hard to clear.
"The difficult part is always showing the perpetrator's state of mind, and the statute requires that there was racial motivation, that the defendant was thinking in racial terms," said William Yeomans, a former Justice Department civil rights lawyer.
The government typically uses evidence such as an attacker's contemporaneous racial epithets, or a pattern of planning to target a specific race, said Samuel Bagenstos, who served in the Justice Department's Civil Rights Division during President Barack Obama's first term.
"If you look at the standard patterns of these cases, there are often statements made by the defendant expressly referring to the race of the victim during the attack," he said.
"That is a cut above the evidence that we've seen so far" against Zimmerman, he added.
In an emergency call before the encounter with Martin, Zimmerman told a police dispatcher that Martin "looks black" but only after the dispatcher asked for Martin's race.
One of the jurors in Zimmerman's state trial told CNN on Monday that she did not think Zimmerman racially profiled Martin. "All of us thought race did not play a role," said the juror, granted anonymity by the television news network.
Further, there is no video of the encounter as there was of King's beating at the hands of four Los Angeles police officers.
After a jury acquitted the officers of state charges in the King case, the Justice Department relied heavily on the video when it tried the officers on federal charges that they deprived King of his civil rights. Prosecutors analyzed the baton blows to King and zeroed in on those that came after the video showed King had been subdued.
The second jury convicted two of the officers, helping to calm a poisonous U.S. racial climate that included riots.
Wayne Budd, who as a Justice Department official oversaw the prosecution of the Los Angeles police officers, said he believed it would be difficult for the government to prove racial animus by Zimmerman with the evidence that has become public so far.
"They're going to have their hands full. It's not going to be easy," Budd said.
Terree Bowers, the U.S. attorney in Los Angeles during the police officers' second trial there in 1993, said prosecutors were able to refine their case the second time around. He said he was not sure the Justice Department could do the same thing against Zimmerman.
"I don't know what else is out there for the government to develop if they decide to proceed," he said.
Holder, the chief U.S. law enforcement official and an Obama appointee, in April 2012 referred to the difficulty of proving racial motivation.
"We have a very ... high bar that we have to meet in order to bring federal charges in this case so we are continuing in that regard," Holder said while addressing Martin's death at a news conference.
A Justice Department statement on Sunday alluded again to the challenges prosecutors face, referring to the "limited" civil rights laws.
One advantage for prosecutors is a change in the hate-crimes law in 2009 that eliminated a requirement that they show a connection between the crime and a federally protected activity, like voting.
A Justice Department spokeswoman on Monday declined to say whether prosecutors had convened a federal grand jury to hear evidence about Zimmerman, a step that would indicate increased activity on the part of prosecutors.