Australian writer Sally Hepworth was at an event promoting one of her books when an elderly woman approached.

The woman said:

I’ve been thinking about murdering my next-door neighbour … I know that I’m going to get away with it … because there are 2 groups of people that are never suspected of murder, & those are old women & little girls (The Book Show, ABC Radio National).

After learning about Mary Bell, she wrote Mad Mabel (2025).

Mabel Waller becomes the young female killer in Australia, convicted of murder in 1959 at the age of 15 & subsequently institutionalised.

The novel shifts between Mabel’s present life as the elderly Elsie Mabel Fitzpatrick, and young Mabel who has a difficult childhood despite the family money.