In Nagano, a daughter hired men to sexually assault her stepsister, intending to remove her from the household due to resentment over her father's remarriage and desire to eliminate her step-sibling.

The second daughter of a famous family in Nagano was raped on the riverbank. In fact, the rapists were men hired by the eldest daughter to get her younger daughter out of the house. The second daughter was a stepchild of her father's second marriage, and the eldest daughter was plotting to get rid of her someday.