So his threats make no sense. If he calls the police there, spidergirl is most likely just gonna vanish, so it's not really a problem. Secondly, so he's kissing a high school girl in his apartment, so what? College students having girlfriends in high school is completely legal in Japan. Sure, she also happens to have the face of the girl who was supposedly murdered, but even so he hasn't committed any crime, so he probably won't be arrested. At most he'll be brought in for questioning.