George Zimmerman, the neighborhood watch volunteer who fatally shot Florida teenager Trayvon Martin 46 days ago, was charged with second-degree murder Wednesday, marking a turning point in a case that has provoked nationwide debate over racial profiling.

Florida special prosecutor Angela B. Corey, who announced the charge in Jacksonville, said that “the search for justice has brought us to this moment.” Zimmerman turned himself in and was brought Wednesday evening to the Seminole County jail.

Criminal justice lawyers said Corey faces an uphill battle in persuading a jury to convict Zimmerman of second-degree murder. Zimmerman told police he was fighting for his life in an altercation with Martin, who was 17 and unarmed, before he fired in self-defense.

Murder in the second degree, under Florida law, refers to a killing carried out without premeditation but with “a depraved mind regardless of human life.” If convicted, Zimmerman faces a maximum sentence of life in prison. His attorney, Mark O’Mara, said Wednesday that Zimmerman will plead not guilty.

A hearing in the case is scheduled for Thursday afternoon.

Martin’s parents applauded Corey’s decision to take Zimmerman into custody, calling it a first step toward justice.

“We simply wanted an arrest,” said Sybrina Fulton, Martin’s mother. “Thank you, Lord.”

His father, Tracy Martin, said: “We got a long way to go, and we have faith. . . . We will continue to hold hands on this journey — white, black and Latino.”

Corey said she had personally informed Martin’s parents of the outcome of her investigation.

“It was less than three weeks ago that we told those sweet parents that we would get answers to all of their questions no matter where our quest for the truth led us,” she said.

Martin was fatally shot Feb. 26 while walking in the Retreat at Twin Lakes, a complex of about 260 peach-colored townhouses in Sanford, Fla. Martin was staying with his father and his father’s fiancee in her townhouse, and he had left briefly to walk to a nearby 7-Eleven to buy a bottle of iced tea and a bag of Skittles.

Zimmerman, 28, who worked at a fraud-detection company, was driving to Target, according to his father. Zimmerman spotted Martin and called 911, saying that there had been a rash of burglaries in the area and that there was “a guy . . . walking around, looking about.”

“This guy looks like . . . he’s on drugs or something,” Zimmerman said.

Before police arrived, Zimmerman and Martin encountered each other in a grassy area between the back yards of two rows of townhouses. Zimmerman says Martin punched him in the face, knocked him down and slammed his head against the pavement.

He has maintained that he was defending himself when he pulled a black Kel-Tec 9mm and shot Martin at close range in the chest after the teenager tried to take the gun. When officers arrived, they found Martin dead in a pool of blood in the grass and Zimmerman bleeding from his nose and the back of his head.

‘Stand your ground’ law

Authorities in Sanford decided not to charge Zimmerman, citing Florida’s “stand your ground” law, which allows a person to use deadly force in self-defense when there is a reasonable belief of a threat and which does not require people to retreat.

Allowing Zimmerman to go free prompted a wave of protests across the country, led in part by Martin’s parents.

The case stirred racial tensions in part because Zimmerman, who is Hispanic, described Martin in his call to police as looking suspicious and “up to no good.” For weeks, the Rev. Al Sharpton and other civil rights leaders have invoked memories of lynching victim Emmett Till and have organized rallies to press for Zimmerman’s arrest. Images of the man and the teenager have played continually on cable television. President Obama weighed in with a comment from the White House: “If I had a son, he’d look like Trayvon.”

Zimmerman’s father has said that his son is not a racist and that he was trying to protect his neighborhood.

Martin’s parents and their attorneys heard the news of the charge on Wednesday in Washington, where they had traveled for the annual convention of the National Action Network, a civil rights organization founded by Sharpton.

“It is about justice, justice and only justice,” said Martin family attorney Benjamin Crump. “We can take a short breath because we are just now getting to first base. This is only first base in this game of justice.”

Zimmerman had been in seclusion for more than 40 days. Two lawyers who have represented him for part of that time, Craig Sonner and Hal Uhrig, announced Tuesday they had lost contact with Zimmerman and could no longer work on his behalf. They voiced concern for his emotional and physical well-being and said Zimmerman had taken actions, such as setting up a Web site soliciting donations and attempting to contact the prosecutor, without consulting them.

‘Focus of anger’

O’Mara, Zimmerman’s new attorney, said he has been troubled by the public outcry against him.

“He has been the focus of anger and maybe confusion and maybe some hatred,” O’Mara said.

An activist group, the New Black Panther Party, had announced that it was raising money to fund a $1 million bounty for the “capture” of Zimmerman.

Corey, a Florida state attorney, was appointed by Gov. Rick Scott (R) to investigate the case after State Attorney Norm Wolfinger recused himself. Wolfinger had scheduled a grand jury for April­ 10, but Corey announced this week that she was not going to bring the Martin case before the grand jury.

In many parts of the country, people gathered around televisions at 6 p.m. Wednesday to watch Corey reveal the preliminary results of her investigation. A small group met in the basement of Allen Chapel AME Church in the historically black Goldsboro neighborhood in Sanford.

As Corey said “justice for Trayvon,” people nodded. When she said “murder in second degree,” they nodded again. And when she said “Mr. Zimmerman is in custody,” a cheer went out and people clapped and said, “Yes, yes, yes.”

Then City Commissioner Velma Williams said: “We did not come here to celebrate. . . . We came here to give thanks to the Almighty that . . . the wheels of justice still do turn. We do not rejoice in anyone’s shortcomings,” she said, adding later that “Mr. Zimmerman has a family, too.”

For a moment, there was relief — and then, for some, apprehension.

“Relief comes in one sense,” Cappila Gaines said as her son walked in from the bright Florida afternoon. “But there is still some type of stress that remains, and we’re hoping there aren’t repercussions” from Zimmerman’s defenders.

Staff writer Stephanie McCrummen in Sanford and staff writer Krissah Thompson and staff researcher Lucy Shackelford in Washington contributed to this report.