Who said "You have a traitor among you."?

This quote is attributed to The White Witch.

You have a traitor among you. - The White Witch

"You have a traitor among you."

The White Witch

Character in The Chronicles of Narnia: The Lion, the Witch and the Wardrobe

"I shall be watching you."

"There is no magic against me."

"One day you might be a King."

"The smaller species prefer my rule to that of the lion."