SANFORD, Fla. -

The neighborhood watch volunteer who shot 17-year-old Trayvon Martin was arrested and charged with second-degree murder Wednesday after months of mounting tensions and protests across the country.
George Zimmerman, 28, could get up to life in prison if convicted in the slaying of the unarmed black teenager.

Special prosecutor Angela Corey announced the charges but would not discuss how she arrived at them or disclose other details of her investigation, saying: "That's why we try cases in court."

Second-degree murder is typically brought in cases when there is a fight or other confrontation that results in death but does not involve a premeditated plan to kill. It carries a mandatory minimum of 25 years behind bars when a gun is used.

Martin's parents expressed relief over the decision to prosecute their son's killer.

"The question I would really like to ask him is, if he could look into Trayvon's eyes and see how innocent he was, would he have then pulled the trigger? Or would he have just let him go on home?" said his father, Tracy Martin.

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Corey would not disclose Zimmerman's whereabouts for his safety but said that he will be in court within 24 hours, at which point he can request bail. He turned himself in in Florida.

Zimmerman's new attorney, Mark O'Mara, said: "I'm expecting a lot of work and hopefully justice in the end."

O'Mara asked that people not jump to conclusions about his client's guilt. He says he's "hoping that the community will calm down" now that charges have been filed and the case is moving forward.

O'Mara also said Zimmerman will plead not guilty to the second-degree murder charge.

On Tuesday, Zimmerman's former lawyers portrayed him as erratic and in precarious mental condition. But O'Mara said Zimmerman was OK: "I'm not concerned about his mental well-being."

Zimmerman, whose father is white and whose mother is Hispanic, has asserted since the Feb. 26 killing in Sanford that he shot in self-defense after the teenager attacked him. Martin's family argued Zimmerman was the aggressor.

The shooting brought demands from black leaders for his arrest, touched off protests in which people wore hooded sweatshirts like the one the teenager had on, and set off a furious nationwide debate over race and self-defense that reached all the way to the White House, where President Barack Obama observed: "If I had a son, he'd look like Trayvon."

Separately, the U.S. Justice Department's civil rights division is conducting its own investigation.

Corey said the decision to bring charges was based on the facts and the law, declaring: "We do not prosecute by public pressure or by petition."

One of the biggest hurdles to Zimmerman's arrest over the past month was Florida's "stand your ground" law, which gives people wide leeway to use deadly force without having to retreat in the face of danger.

Corey repeatedly declined to answer questions about details in the case. "So much information got released on this case that never should have been released. We have to protect this prosecution and this investigation for Trayvon, for George Zimmerman," she said.

READ: Zimmerman charge information

READ: Angela Corey's speech

VIDEO: Angela Corey's speech

After Corey's announcement Wednesday evening, Martin's stepmother, Alicia Martin, said the 45 days it took before the charges against Zimmerman seemed "like a lifetime."

"It's about time, and it's like it took so long, and we was waiting for this day, and the day has come. But, we still have along way to go," she said. "The trial, all of this, this is not done just because he's been arrested. This is just the beginning, and the family is glad."

Alicia Martin said her husband found out about the charges a day or so ago, but she only found out Wednesday that Zimmerman is in custody.