After interviewing 30 people familiar with George Zimmerman, the neighborhood watch captain charged with killing African-American teenager Trayvon Martin, FBI agents found no evidence that the shooting was driven by racial bias or animus.

Before Thursday's release of a Department of Justice report, both sides have argued over whether smatterings of racially charged testimony should be released to the public before the trial – in particular, the testimony of “Witness 9,” whom state prosecutors say has described an “act” by Mr. Zimmerman that suggests “he had a bias toward black people.”

The report released Thursday made clear that the FBI found no one willing to go on the record as saying Zimmerman is racist. Even one of the most skeptical local investigators with the Sanford, Fla., police department, Chris Serino, suggested to the FBI that Zimmerman followed Trayvon “based on his attire,” not “skin color,” and added that he thought Zimmerman had a “little hero complex,” but is not racist, according to the Orlando Sentinel, which obtained copies of the document.

Prosecutors say Zimmerman profiled Trayvon as a criminal (though the teen was doing nothing wrong), followed him, confronted him, and then killed him after a brief scuffle. Zimmerman says he shot Trayvon in self-defense after the teen jumped him, knocked him down, and bashed his head against a sidewalk. The case caused a national uproar over racial profiling and gun laws after local police originally declined to charge Zimmerman. Forty-four days after the shooting, a special state prosecutor charged Zimmerman with second-degree murder.

The report outlines how FBI agents asked each person interviewed whether Zimmerman "displayed any bias, prejudice or irrational attitude against any class of citizen, religious, racial, gender or ethnic groups." No one said he had.

Despite the FBI’s findings, questions about Zimmerman’s mind-set and possible biases could continue to play a part in his upcoming trial. Three weeks ago, Circuit Court Judge Kenneth Lester ruled that the “Witness 9” statements should be released, but both the defense and the prosecution pleaded with him to reconsider. In a previously released statement, Witness 9 is quoted as saying, “I know George, and I know that he does not like black people.”

Mark O’Mara, Zimmerman's lawyer, has vowed to keep such statements out of the jury’s hands, saying they’re irrelevant to the case. But prosecutors say they’re ready to challenge the issue if Zimmerman tries to bolster his defense by suggesting that race did not play a role in his decisionmaking that night.

Other evidence released Thursday included:

Details of an old MySpace account featuring a 21-year-old Zimmerman’s writing voice (he's now 28). At one point, he disparaged Mexicans and gloated over having two felony allegations for accosting a police officer reduced to one misdemeanor. “Workin 96 hours to get a decent pay check, getting knifes pulled on you by every Mexican you run into!” Zimmerman wrote in 2005.

When the Web page was revealed earlier this year, Mr. O’Mara acknowledged that the statements could complicate the legal case if admitted into evidence.

While detailing a slew of robberies in the neighborhood over the winter, the FBI report also includes police documents showing that Zimmerman called 911 four times in the weeks before the shooting to complain about “suspicious” young black males prowling the neighborhood, after a spate of burglaries.

In one such call, Zimmerman described a black man going through trash cans in the neighborhood.

"He keeps going to this guy's house. I know him. I know the resident. He's Caucasian," Zimmerman said. "He is going up to the house and then going along the side of it and then coming straight and then going back to it. I don't know what he's doing. I don't want to approach him, personally."

During his later confrontation with Trayvon, Zimmerman ignored a dispatcher’s warning to stop following the person he had described as a suspicoius black man, and at one point mumbled, “These [expletive] always get away.”

Zimmerman is half-white and half-Hispanic. His family has testified that he was a mentor to two poor black kids in the Orlando, Fla., area, and rallied the community to help a homeless black man who had been sucker-punched by a police officer.

But questions about Zimmerman’s character and credibility have intensified this summer, after the judge remanded him back to jail for conspiring with his wife, Shellie, to lie about their finances so as to secure a lower bond, and perhaps to plan an escape from the US to flee prosecution. He was rereleased from jail last week on a $1 million bond.