Do defendants have a right to info from "anonymous" tipster lines?

In North Carolina, two men facing murder charges are demanding to see the information collected by the local CrimeStoppers hotline -- which received anonymous tips that led to their being charged in a young woman's slaying. They argue they need that information to see what other leads might have been ignored by police. The district attorney is worried, though, that it'll undermine the hotline's promise of anonymity and lead people to stop calling in tips.