Trayvon Marin: Protestors, social media demand answers Florida residents are no longer alone in their demand for answers in the case of Trayvon Martin, a 17-year-old black teenager who was walking unarmed through a gated community in Sanford, Fla., last month when he was shot and killed by a neighborhood-watch captain. The volunteer, identified by authorities in the case as George Zimmerman, 28, has said he was acting in self-defense. But much of the country wants to know: Why hasn't Zimmerman been arrested? The slaying has dominated social media and national news outlets in the wake of Friday's release of 911 tapes in the Feb. 26 shooting. On the tapes is Zimmerman's call to report Martin. "He's got his hand in his waistband and he's a black male," Zimmerman can be heard telling the dispatcher, saying he's following Martin. "We don't need you to do that," the dispatcher told him. But Zimmerman continued to follow Martin. Moments later, shots were fired. The teen, who was walking back from a store, was carrying only a cellphone, a bag of Skittles candy and an iced tea, authorities say. The state attorney's office is reviewing the events leading up to the shooting. But some see race as a factor in the seeming lack of progress in the 3-week-old case. Critics of the investigation have held marches and protests at Florida A&M University and outside the criminal courts building in Sanford. The Rev. Al Sharpton -- a civil right activist-turned-MSNBC show host -- has announced plans for a Thursday rally. On Twitter, social media users were urged to flood the U.S. Justice Department with demands for justice, and several Change.org petitions are being circulated, including: Prosecute the killer of 17-year-old Trayvon Martin. It has more than 398,000 signatures so far. Celebrities such as Alyssa Milano and Blair Underwood were using their Twitter and Facebook feeds to draw attention to the case. The teen's parents have also formally asked the FBI to step in. Tracy Martin, the boy's father, told CBS news that the fact that Zimmerman remains free means that his son is being portrayed as the culprit. "They're treating this as if my son is 'the perp,'" he said, "My son is the victim here." He added: "It can't be self-defense. What was he gonna do, attack him with a bag of Skittles? The case is also casting a spotlight on Florida's so-called "stand your ground" law. That law gives individuals the leeway to use deadly force if they feel threatened. Underwood posted on his Facebook page that the case caused him to have a serious talk with his own son: I had a talk with my son the other night explaining to him that some backwards thinking idiots in this world won't see his beautiful, brilliant mind and spirit first. "SOME" will see his "BEAUTIFUL" black skin first ... and be threatened by it. True, that is their problem, but when that idiot carries a gun, it is important that our children be armed with information/street-sense and know not to escalate the situation...in that moment. Let cooler heads prevail, then nail them through the media and/or the justice system! Want a sniff? Corpse plant reeks of rotting flesh Tennessee bill could require publishing names of abortion doctors New York chef promotes roaches, other insects as food of the future