Su (left) with the main cast of the film in a promotional event.

"I didn't think much about this at the beginning ... But when more comments emerged online, I was scared," he says.

In the movie－unlike most crime thrillers where the audience does not know who the criminal is until the end－the killer is known, and the story is about a cat-and-mouse game between the police and the highly intelligent criminal.

The Chinese translation of the novel was a best-seller on Amazon's China subsidiary in 2016.

"As fans know what will happen, it makes the adaptation more difficult. You need to be faithful to the original story as well as go for innovation," Su says.

Su attempted to maximize localization, revise the emotional aspects, restructure the timeline and focus on details.

The movie, while still centered on a desperate single mother's accidental killing of her abusive ex-husband, makes the plot an intellectual duel between two male protagonists－the woman's next-door neighbor, a mathematics genius who helps her devise a cover-up, and a physics scholar, who assists the police.