New York (CNN) -- The February 26 shooting of Trayvon Martin, a black teenager, by George Zimmerman, who is Hispanic, has in less than a month gone from a local story to a huge national story. As we all now know, Martin got into a confrontation with Zimmerman, a neighborhood watch captain patrolling a gated community in Sanford, Florida. Their confrontation ended when Zimmerman, who is licensed to carry a concealed weapon, shot the unarmed Martin. When the police failed to arrest Zimmerman partly because of the state's strong self-defense "stand your ground" law, the case raised outcries of racial injustice.
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State prosecutors have not brought charges in shooting death of Trayvon Martin
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Nicolaus Mills says the news that the federal government will investigate is welcome
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He says in 1964, the Civil Rights Division was able to obtain convictions in three killings
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Mills: The current federal investigation could help establish facts, defuse tensions
This version of events, questioned by some in the wake of a newly released video of a seemingly unhurt @placeholder in police custody, has been fodder for a counterattack on Martin's defenders.