SANFORD, Fla. (AP) — George Zimmerman, the neighborhood watch volunteer who fatally shot unarmed black teenager Trayvon Martin in Florida, will be charged in the 17-year-old’s death, a law enforcement official said Wednesday.

Special prosecutor Angela Corey will announce charges against the 28-year-old Zimmerman at a 6 p.m. Wednesday news conference, the official with knowledge of the investigation told The Associated Press. Corey confirmed that an announcement on the case would be made in Jacksonville but didn’t elaborate. The person said Zimmerman’s arrest is also expected soon.

The official didn’t know the charge and spoke on condition of anonymity because he wasn’t authorized to release the information.

Trayvon Martin’s mother Sybrina Fulton, left, listens to the family attorney Benjamin Crump, during a news conference at the Washington Convention Center in Washington, Wednesday, April 11, 2012.

Corey had said late Tuesday, after Zimmerman’s attorneys announced they were withdrawing from the case, that she would have an announcement on charges within 72 hours.

The two attorneys said they no longer were representing Zimmerman because they haven’t heard from him since Sunday.

“As of the last couple days, he has not returned phone calls, text messages or emails,” attorney Craig Sonner said. “He’s gone on his own. I’m not sure what he’s doing or who he’s talking to.”

However, the person with knowledge of the case said law enforcement knows where Zimmerman is. His former attorneys have said he is in hiding and suffering from high levels of stress from the intense public scrutiny he is under.

Trayvon Martin in an undated family photo.

On Wednesday, Attorney General Eric Holder also said the Justice Department is conducting a thorough and independent review of the case after launching its own investigation three weeks ago.

Zimmerman said he shot Martin in self-defense after following the teenager in a Sanford, Fla., a gated community outside Orlando on Feb. 26. He said he was returning to his truck when Martin attacked him and that he shot the unarmed teen during the fight. He wasn’t arrested partly because of Florida’s “stand your ground” self-defense law, which gives people wide leeway to use deadly force.

The lack of an arrest has led to protests across the nation and spurred a debate about race and the laws of self-defense. Zimmerman’s father is white and his mother is Hispanic.

2. This Is George Zimmerman

George Zimmerman is a 28-year-old resident of Sanford, Florida, where Trayvon Martin’s father, Tracy Martin, is also a resident. Zimmerman was a self-appointed neighborhood watchman who had called the Sanford 911 nearly 50 times since January 2011 to report suspicious behavior. He himself has had run-ins with the law, including an arrest in 2005 for assaulting a law enforcement officer (where the mugshot above was taken) and allegations of domestic violence.

3. The Night Of February 26th

Trayvon Martin was visiting his father in Sanford, Florida on the evening of February, 26th, 2012. They were watching the NBA All Star game at his father’s girlfriend’s home when Trayvon decided to go to the local 7-11 and buy some snacks for everyone. Trayvon purchased Skittles and Arizona Iced Tea.

4. The Walk Home

It was a rainy night on February, 26th. Trayvon was wearing a hoodie as he headed back from the 7-11. His path took him by the gated community of Twin Lakes, where George Zimmerman lived.

5. The 911 Call

Zimmerman spots Trayvon and begins following him in his car. Zimmerman calls 911 and is told not to pursue. Zimmerman ignores the dispatcher and gets out of his car to confront Trayvon. In the same phone call, Zimmerman utters something under his breath that some have interpreted as the racial slur “coon.” Others claim he is saying “punk.” Zimmerman is armed with a 9mm semiautomatic handgun.

6. The Call To His Girlfriend

Trayvon realized he was being followed by Zimmerman while he was on the phone with his girlfriend. “He said this man was watching him, so he put his hoodie on. He said he lost the man,” said his 16-year-old girlfriend (who, as a minor, has not been identified). “I asked Trayvon to run, and he said he was going to walk fast. I told him to run but he said he was not going to run. Trayvon said, ‘What are you following me for,’ and the man said, ‘What are you doing here.’ Next thing I hear is somebody pushing, and somebody pushed Trayvon because the headset just fell. I called him again and he didn’t answer the phone.”

7. A Shot Is Fired

911 is inundated with phone calls from the Twin Lakes neighborhood describing an altercation. In one call, you can hear screams followed by a shot. The screams stop. Trayvon Martin has been killed by a gunshot to the chest. He is only 70 yards from his father’s girlfriend’s home.

8. “Stand Your Ground” Law

Even though Zimmerman confessed to shooting Trayvon, who was unarmed, he has not been charged with any crime. Zimmerman is being shielded by Florida’s Stand Your Ground Law, which gives wide latitude to homicide in the name of self-defense. Since Zimmerman claims he felt threatened and was partially bloodied in the altercation, Sanford police claim they have no grounds for an arrest.

9. The Federal Government Steps In

Following widespread condemnation of how the Sanford police handled the case, the Justice Department has announced it will launch its own investigation into the death of Trayvon Martin, and a grand jury is being called by authorities in Florida. The Sanford City Commission voted 3-2 that it had no confidence in the Sanford Police Chief.