The situation from this event is unbelievable the girl that was trying to be cautious at a certain degree goes to meet with the most 100% culprit of the dissapareance and possible death of her sister (don't forget she gets this info from the person more near to him in the club and she almost get rap by that same person with the help of an accomplish that he was blackmailing), alone without regard of any security of what could happen to her.
She could get kill if you also remember that in this time two years ago a student's corpse (Harada Kasumi) was found inside a suitcase and the names of Shiraishi and Takeda where found un her contacts and the police thinks the club and Kajiwara has something to do with that.
Also the logic writing of the police is absurd, How can they not take the disappearance of a person who has been missing for over a year as something serious, and even more so if the club and the group being investigated for white slavery are linked to the case of the body found in the river?
They skip this plot point or what?