The Justice Department and the FBI's decision to launch an investigation into the shooting of Trayvon Martin, a black teenager who was shot while walking on a neighborhood street unarmed, has launched a debate inside the agency about how difficult it might be to bring federal charges. Martin was shot by George Zimmerman, a neighborhood watch volunteer, who told police Martin "looked up to no good" and that he acted in self-defense. Civil-rights law protects against hate crimes and police abuses, but officials said the shooting may not fall into either category.
