Florida special prosecutor Angela Corey plans to announce as early as Wednesday afternoon that she is charging neighborhood watch volunteer George Zimmerman  in the shooting of Trayvon Martin , according to a law enforcement official close to the investigation.
It was not immediately clear what charge Zimmerman will face.
Martin, 17 and unarmed, was shot and killed Feb. 26 by Zimmerman, who said he was acting in self-defense. Police in Sanford, Fla., where the shooting took place, did not charge Zimmerman, citing the state’s “stand your ground” law.
Corey told reporters Tuesday night that she would hold a news conference about the case within 72 hours. A news release from her office said the event will be held in Sanford or Jacksonville, Fla.
Benjamin Crump, who is representing the Martin family, said this week that Corey’s office had asked where Trayvon’s parents would be each day this week. They arrived Wednesday in Washington for a civil rights conference organized by the Rev. Al Sharpton, where they are scheduled to speak.
This story is developing ...
Update: 2:43 p.m. EST
According to CNN.com:
A special prosecutor in the Trayvon Martin shooting case  is expected to announce a decision within the next four hours regarding whether she will file charges against George Zimmerman, CNN reports.
The news comes a day after attorneys for Zimmerman told reporters they had lost contact with Zimmerman and no longer represent him .
Update 2:46 p.m. EST:
NBC News  confirms the report.
On Tuesday night, Florida special prosecutor Angela Corey told reporters that she would hold a news conference with an announcement on the case within 72 hours. According to a law enforcement official close to the investigation, Corey's office plans to announce that she is charging the neighborhood watch volunteer as early as Wednesday afternoon.
The news came shortly after a bizarre press conference  where Zimmerman's lawyers said they will no be longer be representing him, claiming he repeatedly rebuffed their legal advice and that they had lost contact with him.
"As of now we are withdrawing as counsel for Mr. Zimmerman," Craig Sonner, one of his attorneys, told reporters outside the Seminole County Courthouse in Sanford, Fla. "He's gone on his own. I'm not sure what he's doing or who he's talking to, but at this point we're withdrawing as counsel. If he wants us to come back as counsel, he will contact us."
Zimmerman said he killed Trayvon Martin , an unarmed 17-year-old, on Feb. 26 in the gated community where the girlfriend of the teenager's father lived in Sanford. Zimmerman, a neighborhood watch member, called 911 and told a police dispatcher that Martin, who was returning from a trip to a nearby convenience store, "looked suspicious." After an altercation, Zimmerman shot Martin in the chest. He told the local police that he shot Martin in self defense, and was not arrested or charged.
Corey announced earlier this week that she would not be convening a grand jury in the case. Experts familiar with Corey's background say she has a reputation of avoiding grand juries in cases in which they are unnecessary. Under Florida law, murder charges can only be issued by a grand jury. Zimmerman may face other charges in the shooting death, including manslaughter and assault.
Update 3:14 p.m. EST
Special prosecutor has scheduled a news conference to make an announcement about charges in the Trayvon Martin case at 6 p.m. EST Wednesday. Trayvon's mother, Sybrina Fulton, tweeted the following message: We're on pins&needles waiting for Ms. Coreys decision but we're prayerful that justice will prevail. He sits high&looks low #GODisincontrol 
Fulton and Trayvon's father, along with their attorney, appeared on CNN's Piers Morgan program earlier this week. Below is the video of their appearance: