"I feel like we're back in the wild, wild West", says Bonnie Baker, who lost her 21-year-old son in similar circumstances to the Trayvon Martin murder. Her son's killer, who police wouldn't even arrest, "took it upon himself to be the policeman, the judge and the executioner", she says. The right to bear arms has long divided opinion in the United States, but Florida's 'Stand Your Ground' gun law has been especially controversial, allowing people to use lethal force if they feel threatened, and not just in their own homes. Since it was introduced in 2005, the rate of justifiable homicide has almost tripled: Trayvon's parents aren't alone in their grief and anger. After six weeks of investigation and under enormous public pressure George Zimmerman has finally been charged for killing Trayvon. Yet similar gun laws apply in more than 20 states in the US and most cases are never prosecuted. Is this "law for law-abiding citizens" literally letting people get away with murder?