A federal grand jury will meet in downtown Orlando Wednesday to hear testimony about whether Trayvon Martin's civil rights were violated when Neighborhood Watch volunteer George Zimmerman shot him in the chest, according to court paperwork.. A U.S. Department of Justice attorney from Washington, D.C., Mark Blumberg, has issued at least one subpoena for Wednesday in the case. Blumberg would not comment on the grand jury session, but the federal panel is to meet at 9 a.m. at the federal courts building on Central Avenue in downtown Orlando to hear evidence in the case. It's not clear how many witnesses...