Celeb Beef: Bieber Fires Back Over CSI ‘Brat’ Comments (AUDIO)

Justin Bieber has haters. He knows it. We know it. But his latest hater is CSI star Marg Helgenberger, claiming that when the Biebs was on set for his guest role on CSI he was "a brat." This story, which mentions Bieber locking a producer in a closet and putting his fist through a cake, has made it's way around the interwebz and audio proof has surfaced online from the original radio interview in which Helgenberger made her claims.
Bieber called a brat by matt-stopera

Bieber has fired back at Marg in a place where he knows he is surrounded with support; on Twitter.

So we wanna know .. Is Marg a bully ? Or do you think Bieber is really a brat ?