Like others predicted, the butler with glasses, Will, is the culprit.
Considering what happened here, maybe he can still be turned into an ally. Yeah, so he tried to kill her, but in the grand scheme of things it's basically a misunderstanding since the Jelly now is not really the old Jelly. Maybe there's a chance to talk things out. I wonder if he'll get to know her secret?
I hope whatever happened to Emma isn't too dark...