Dai Gotei ni Nokosa Reta Yomeshuto (1984)

Dai Gotei ni Nokosa Reta Yomeshuto 1984 / 大豪邸に残された嫁姑 1984 / The Bride-in-Law Left in the Mansion

Doctor Akaji, is found dead in his own clinic. Soon, it turns out that the man was in relationship with woman named Utako. Investigators learn about this from the woman's mother-in-law, because Utako is married and Akaji was her lover. Although the perpetrator and the motive seem obvious, everything changes when Utako is found dead. Is it a coincidence? (Source: XuongPhim) ~Adapted from Jokichi Hikage's ‟Iccho Rinatsu Murder Case‟.