Molester's Train: Seiko's Ass (1985)

Who is it that sends a threatening letter demanding 100 million yen in exchange for distributing "poisoned rice" to boost sales of a famous brand of rice? As instructed, the bag of rice stuffed with money is thrown from the railway bridge into the riverbank. A street performer gets caught up in an incident through an unexpected incident and contacts a woman who is thought to be an accomplice in an attempt to clear his name, but the incident eventually escalates into murder...