Three years after teen Trayvon Martin was fatally shot by George Zimmerman in Sanford, Fla., setting off a national debate on race and gun laws, the Department of Justice is expected to conclude there is not enough evidence to bring civil rights charges in the case, a source tells CBS News.
On Feb. 26, 2012, Martin was walking back from a convenience store after purchasing a pack of Skittles candy and iced tea when Zimmerman, a neighborhood watch volunteer, confronted him. The 17-year-old was visiting his father's fiancée at The Retreat at Twin Lakes community in Sanford with his father, and was wearing a hooded sweatshirt.
Zimmerman told police immediately after the incident he killed the teen in self-defense after a scuffle. He was taken into custody but was released without charges being filed. The police chief in Sanford, Bill Lee, who later resigned, said Zimmerman was not arrested because his story held up under Florida's now much-debated "Stand Your Ground" laws.
About a month later, the story started making national headlines, as it was revealed that Martin was black and unarmed and that Zimmerman faced the prospects of no legal penalty. Media began reporting Zimmerman as being white, but his family insisted he was Latino.
On March 19, 2012, the Justice Department announced it would open an investigation into the case.
Attorney General Eric Holder expressed personal interest in the case, saying at the time: "At every level of today's Justice Department -- preventing and combating youth violence and victimization is, and will continue to be, a top priority."
After details of the incident began to leak - including 911 tapes and videos of Zimmerman in custody - as well as several back-and-forths about criminal charges from state and local officials, special prosecutor Angela Corey announced on April 11, 2012, that Zimmerman was being charged with second-degree murder in the shooting and that he was in police custody.
He was acquitted of murder charges on July 14, 2013, in a case that divided an all-female jury panel and set off nationwide protests.
The national race debate that the Trayvon Martin case began was later further inflamed by the shooting of Michael Brown in Ferguson, Mo., and the chokehold death of Eric Garner in Staten Island, N.Y., among other cases.
The Department of Justice also opened a civil rights investigation into each of those cases. It declined to press charges against former Ferguson police officer Darren Wilson in the case of the Michael Brown shooting. The decision regarding the Eric Garner case is still open.
Zimmerman has since slipped into relative obscurity, and has had several other run-ins with police, mostly involving domestic disturbances.
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