The shooting of an unarmed American teenager by a self-appointed volunteer monitoring a Florida neighbourhood has raised new questions about the role and boundaries of neighbourhood watch programmes.
In place since the 1970s, neighbourhood watch programmes have been seen as a largely successful endeavour in the United States, but the shooting of 17-year-old Trayvon Martin, with only a bag of skittles on his person, has the nation asking important questions about where to draw the line between protection and murder.
Al Jazeera's Andy Gallacher reports from Miami.
