Leonarda Cianciulli's story is infamous, but many of the stories online are sensationalist quickies, meant to draw in the reader for the juiciest details. However, as with many female murderers-her story is nuanced and more than meets the eye.
TRIGGER WARNING: there are descriptions of sexual assault in this episode pretty early on. If this is an issue for you, they're skippable and aren't a central part of the story.
references:
wikipedia
The Serial Series Part 3: Leonarda Cianciulli, by Sierra Brugni