Amelia could not understand how Margaret could place her as the person behind her father's death when there wasn't any evidence. Did Killian and Margaret have a conversation?
If there was a possibility Margaret had someone watching her, Cyrus would have noticed them and disposed of the person. He always did when her father had someone watching her. Margaret was right when she said she would always know what is happening inside the castle.
Amelia decided not to comment on her grandmother's words. She had been scared for her grandmother to find out what she had done but her father's death was easily accepted.