MIAMI — Without filing hate-crime charges against former neighborhood watch leader George Zimmerman, the Justice Department on Tuesday closed its investigation into the fatal shooting three years ago of Trayvon Martin, the unarmed black teenager who became a symbol of racial profiling and Florida's "stand your ground'' law.
The department began a civil rights investigation shortly after a national furor erupted over Martin's death, which set off protests, demands for justice and an emotional response from President Barack Obama. The shooting was the first in a string of racially tinged cases involving the deaths of young black men that have prompted an examination of the nation's criminal justice system and police procedure.
Zimmerman was acquitted in a Florida court of second-degree murder in 2013; some jurors said they believed that Zimmerman shot Martin, 17, in self-defense.
Officials from the Justice Department and the FBI met with Martin's parents, Sybrina Fulton and Tracy Martin, Tuesday in Miami to inform them about the decision not to bring federal charges.
Martin's parents were badly shaken by the news, said the family's lawyer, Benjamin L. Crump.
"This is very painful for them; they are heartbroken," Crump said. "But they have renewed energy to say that we are going to fight harder to make sure that this doesn't happen to anybody else's child."
Martin and Fulton have become national figures and, through their foundation, are trying to help reduce violence in black and Hispanic communities and improve education.
Zimmerman's lawyer, Don West, was on a flight and couldn't immediately comment on the decision. Zimmerman, 31, could not be reached for comment.
The bar for prosecuting hate crimes is high; proving negligence or recklessness is not enough. Zimmerman's trial lawyer, Mark O'Mara, has said there is no evidence that his client was racist, citing the fact that he had black friends and saying that he had mentored two black youths.
Federal investigators said they examined the case under multiple civil rights provisions, including ones that make it illegal to use force against someone based on their race and another that criminalizes race-based interference with a person's housing rights, the Miami Herald reported.
The FBI and federal prosecutors reviewed the evidence in the state case as well independently interviewing 75 witnesses. They looked at Zimmerman's numerous brushes with the law after his acquittal — and even hired a "biomechanical expert" to evaluate Zimmerman's descriptions of the violent struggle, the Herald reported.
But the hurdle in Zimmerman's case was proving his intent, said former federal prosecutor Richard Scruggs, who used to oversee civil rights cases in Miami.
"You would have to prove Zimmerman knew it was illegal to use a deadly weapon against Trayvon because of his race, and decided to do it anyway," Scruggs said. "The way the facts developed at trial, there was just no proof of that whatsoever."
The conclusion of the Justice Department investigation came as Attorney General Eric Holder Jr. completes his term in office. It was one of several racially fraught cases that he said the department would finish investigating before he stepped down. The Justice Department is also conducting two separate civil rights investigations into the fatal shooting of Michael Brown, another unarmed black teenager, who was killed by a white police officer in Ferguson, Mo., in August. In that case, violent demonstrations erupted after the shooting. A grand jury declined to indict the officer.
"The death of Trayvon Martin was a devastating tragedy," Holder said in a statement. "It shook an entire community, drew the attention of millions across the nation, and sparked a painful but necessary dialogue throughout the country.
"Though a comprehensive investigation found that the high standard for a federal hate crime prosecution cannot be met under the circumstances here, this young man's premature death necessitates that we continue the dialogue and be unafraid of confronting the issues and tensions his passing brought to the surface. We, as a nation, must take concrete steps to ensure that such incidents do not occur in the future."
The federal inquiry was started to pursue "an independent investigation" into the shooting after local police officials and prosecutors were slow to arrest and charge Zimmerman; they argued that Florida's self-defense laws would make it difficult to prove a criminal case. Gov. Rick Scott then appointed a special prosecutor who eventually charged Zimmerman.
Zimmerman's case also swirled, to a large extent, around issues of race. Prosecutors said Zimmerman forced a confrontation with Martin on Feb. 26, 2012, because Martin was an unfamiliar, tall black teenager wearing a hoodie walking around Zimmerman's gated community one rainy night. Martin was in Sanford with his father, visiting his father's fiancee, who lived in the gated community.
A rash of burglaries in the area had heightened Zimmerman's concerns and, as the neighborhood watch leader, he said, he was suspicious of Martin. He got out of his car — ignoring the advice of a police dispatcher — and followed Martin, setting off a confrontation, prosecutors said.
Angry at Zimmerman and feeling threatened, prosecutors said, Martin pushed him to the ground, punched him and slammed his head into the pavement. Zimmerman, flat on his back, took out a gun and killed Martin. He told the police it was self-defense.