Gukoroku - Traces of Sin (2017)

Tanaka is going through a tough time trying to support his younger sister Mitsuko, recently arrested and on hold in jail. An investigative reporter, he immerses himself into a story about a shocking murder case gone cold. The "perfect" family – successful businessman, beautiful wife and adorable child – were brutally murdered a year ago and the case remains unsolved. Tanaka interviews their friends and acquaintances, and as stories of their true nature unfold, he begins to discover that the family was not as ideal as believed.