Zimmerman's original tweet showed photographs of Trayvon Martin -- who was shot last year in a gated community in Sanford, Fla. -- and De'Marquise Kareem Elkins, 17, CBS News reported. Elkins has been charged in Georgia with killing Antonio Santiago, a 13-month-old who was shot March 21 in an attempted robbery of his mother.
George Zimmerman, a community watch volunteer, says he acted in self-defense when he shot Martin. He persisted in following martin, who was 17 when he was killed, after a police dispatcher told him to back off.
Robert Zimmerman sent his first tweet to a list of organizations, including the National Association for the Advancement of Colored People and the National Rifle Association. He showed both Martin and Elkins with middle fingers extended with the message: "A picture speaks a thousand words. Any questions?"
George Zimmerman's lawyer, Mark O'Mara, told the Daily Beast Tuesday Robert Zimmerman is not helping his brother's case.
"I don't know what was in his heart, but his words and his tweets tend to just rip people apart," O'Mara said. "To tie someone like Trayvon Martin to a person who seems to have committed a heinous murder, just because they share a common trait of being black and having fingers, is wholly inappropriate. It allows people to start calling each other racists again."
2014: The Year in Music [PHOTOS]