Zimmerman prosecutors face hurdles

Prosecutors face steep hurdles to win a second-degree murder conviction against a neighbourhood watch volunteer charged in the shooting death of unarmed teenager Trayvon Martin, experts say.

George Zimmerman was charged after a public campaign to make an arrest in the shooting that galvanised the US for weeks. Now the prosecutor and her team will have to prove Zimmerman intentionally went after Martin instead of shooting him in self-defence, to refute arguments that a Florida law empowered him to use deadly force.