WASHINGTON (AP) - Law enforcement officials say state attorney will announce criminal charges against George Zimmerman at a press conference at 6pm on Wednesday.

Trayvon Martin's parents renewed their calls for calm as a special prosecutor in Florida neared a decision on whether to charge neighborhood watch volunteer George Zimmerman in Martin's death.

Martin's mother Sybrina Fulton says she knows "justice will be served" in her son's death. Zimmerman was not jailed or charged and has said he shot Martin in self-defense.

Attorney Benjamin Crump said the family wants communities nationwide to remain calm in response to the prosecutor's decision. "We don't need anybody taking these matters into their own hands," Crump said.

Fulton and Trayvon's father Tracy Martin spoke at a news conference in Washington, where Attorney General Eric Holder said earlier that he would take appropriate action if evidence of a civil rights crime is found in the shooting.