The primary colored butterfly was watching - the smell of death (1978)

Sinopsis

One night, a passenger car driven by Kyoko hit and killed a woman. Her husband, Dr. Nogami, who was a passenger in the car, hid the body in the grass and they returned home. Soon after, an autopsy by the police revealed the identity of the woman. A few days later, the woman's lover, Ueda, calls Nogami demanding that he keep quiet.