Tuesday marked one year since Trayvon Martin, 17, was killed. He was shot by George Zimmerman, a neighborhood watch captain who claims self-defense. Last Friday, a 19-member task force commissioned by Florida's governor to study the state's controversial "Stand Your Ground" self-defense law announced they found no reason to make changes to it. George Zimmmerman has pleaded guilty to second-degree murder in the shooting death of Martin. But in April, his defense attorney's plan to ask the court to dismiss all charges against their client under that law.