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.