Final answer:
The blame for Geraldine's black cat's death is ambiguous but suggests involvement in criminal activity or witchcraft. A metaphorical connection is drawn to the death of a bird, possibly insinuating misplaced blame.
Step-by-step explanation:
Based on the passages provided, it seems that the blame for the death of Geraldine's black cat is being directed at a person involved with witchcraft or someone who had deliberately targeted the cat as part of a criminal or malicious act. The ransom note, the type-written demand for money, and the suspicion towards a British native suggest that the death of the cat was part of a larger plot or crime.
However, there is also an insinuation that the cat was involved in the death of a bird, as inferred from the discussion between Mrs. Peters and Mrs. Hale about a missing bird, hinting that the cat caught it. This insight could be metaphorical for the broader mystery at hand, perhaps suggesting that someone as unsuspecting as a cat might be blamed for something more nefarious.