"Dead?" said Mrs. Samsa and looked inquiringly at the cleaning woman, although she could scrutinize everything for herself and could recognize the truth even without scrutiny. "I'll say," said the cleaning woman (3.31)
As in Quote #6 above, the cleaning woman seems to have an unusually close tie to Gregor, at least closer than his family. It's the cleaning woman, and not any of the Samsas, who definitively declares Gregor dead. Perhaps she has some special knowledge of who – and what – he is in a way that the Samsas don't, even though he's part of their family.