How do you hurt the white banshee in fable 2?

It's a mission given to you by Sam and Max, they unleashed a Banshee in Bloodstone, I killed all the little demon girls but it doesn't daze, it fades off and reappears some wheres else. So I just swing my sword at it, nothing, my gun, nothing, and even my magic. Are you suppose to lure it somewheres or what, because nothing seems to hurt it.