Cephus Johnson (R) of Oakland, California, visits a memorial for Trayvon Martin in Sanford, Florida March 25, 2012. Martin, 17, was shot dead on February 26 after George Zimmerman, 28, a white Hispanic neighborhood watch captain, believed the young man walking through the gated community in a hoodie looked suspicious. Zimmerman followed him and an altercation ensued. Zimmerman has said he was acting in self-defense. He has not been arrested, though state and federal authorities are investigating. Johnson is the uncle of Oscar Grant, who was shot and killed by a Bay Area Rapid Transit police officer in Oakland, California on New Year’s Day in 2009. REUTERS/David Manning (UNITED STATES – Tags: CRIME LAW CIVIL UNREST SOCIETY)