Christie's female killers

Hi guys, I have a question about our beloved Agatha Christie, specifically her female killers. I'm doing a little research on the emotional baggage that some female characters carry, which explains why they commit murder. Some examples could be:

- The Mirror Crack’d from Side to Side

- A Murder Is Announced

- Murder on the Orient Express

- At Bertram's Hotel (movie version)

Do you have any other suggestions for books where women have deep and emotional motives for committing murder?