Legal experts specializing in civil rights stated on Monday that unless federal prosecutors can provide fresh evidence indicating that racial bias motivated George Zimmerman, a man of white and Hispanic descent, to shoot Trayvon Martin, an unarmed black teenager, they are unlikely to pursue charges against him. Zimmerman, a 29-year-old neighborhood watch volunteer, was acquitted of second-degree murder and manslaughter charges in the 2012 shooting death of Martin by a jury in Sanford, Florida. Defense attorneys claimed that Zimmerman shot the 17-year-old Martin in self-defense. Both state and federal courts typically require the same level of evidence for a criminal conviction: proof of guilt beyond a reasonable doubt by a unanimous jury or a judge if a defendant opts for a trial without a jury. The Seminole County jury's decision to find Zimmerman not guilty of second-degree murder indicates that they did not believe he acted with malice, spite, or hatred. Attorney General Eric Holder stated that the Justice Department has not yet made a decision on whether to pursue federal civil rights charges against Zimmerman. The case, similar to past incidents such as the Rodney King beating and the Sean Bell shooting, highlights the federal government's role in enforcing civil rights. Preachers, including Al Sharpton, planned to hold a news conference at the Justice Department headquarters to push for Zimmerman's prosecution, as they believe he racially profiled Martin before chasing him with a 9mm pistol. The Hate Crimes Law, passed in 2009, would likely be the law federal prosecutors would use against Zimmerman. Prosecutors must demonstrate that an individual caused physical harm to another person "because of the actual or perceived race" of the victim, a requirement that can be challenging to meet. According to William Yeomans, a former civil rights lawyer at the Justice Department, the key difficulty lies in proving the perpetrator's state of mind, as the law mandates that racial motivation was a factor in the crime. Samuel Bagenstos, who worked in the Civil Rights Division under President Obama, explained that the government typically relies on evidence such as racial slurs or a pattern of targeting a specific race to build their case. Bagenstos noted that in many cases, attackers make explicit references to the victim's race during the assault, which sets a high standard of evidence not yet seen in the case against Zimmerman. Before encountering Martin, Zimmerman mentioned to a police dispatcher that Martin "looks black" only after being asked about Martin's race. A juror from Zimmerman's state trial told CNN that she did not believe Zimmerman racially profiled Martin, and that race was not a factor in their decision. Unlike in the case of Rodney King, there is no video evidence of the encounter between Zimmerman and Martin. The Justice Department used the video of King's beating by Los Angeles police officers as evidence in their federal charges against the officers after they were acquitted on state charges. Prosecutors examined the baton strikes to King and focused on those that occurred after he had been subdued in the video. Two officers were convicted by the second jury, helping to soothe tensions in the racially charged US climate that had led to riots. Wayne Budd, who supervised the prosecution of the Los Angeles police officers as a Justice Department official, expressed doubts about proving racial bias by Zimmerman based on the evidence currently available. Terree Bowers, the US attorney in Los Angeles during the officers' second trial in 1993, noted that prosecutors were able to improve their case in the second trial. He expressed uncertainty about the Justice Department's ability to take action against Zimmerman, stating that he was unsure of what additional evidence the government could gather if they chose to move forward. Holder, the top US law enforcement official appointed by Obama, mentioned the challenge of proving racial motivation in April 2012. He emphasized the high standard required to bring federal charges in this case and stated that they were still working towards meeting that standard in regards to Martin's death. The Justice Department also mentioned the difficulties prosecutors face, specifically citing the limitations of civil rights laws. A benefit for prosecutors is the removal of a requirement in the hate-crimes law in 2009 that necessitated a connection between the crime and a federally protected activity such as voting. A Justice Department spokeswoman did not confirm on Monday if prosecutors had called a federal grand jury to review evidence on Zimmerman, which would suggest heightened prosecutorial activity.