According to K C Johnson, North Carolina has no legal means to rein in a rogue DA except by him losing an election. (In other states the Governor, the Attorney General or sometimes the Supreme Court can do it.) If the electorate approves of the rogue DA then he's in and there's nothing anyone in government can do about it.
There's a prior thread here
http://www.freerepublic.com/focus/f-chat/1726850/posts?page=118#118
And the one before that is full of good stuff too
http://www.freerepublic.com/focus/chat/1721830/posts?page=682
So when is this rogue DA up for election again?