Haruka and Yakumo saw the ghost of the little girl over Isshin and followed it to the room of Mamiya Yoshiko, the little girl in the wheelchair that Isshin met in the hospital. Yakumo found out that Yoshiko is the daughter of the Prof Sakakibara, the attending doctor on the night that Isshin was attacked. He found further proof that Prof Sakakibara was the actual attacker of his uncle (from the damaged mirror that he side swiped when he was rushing back to the temple). His motivation for attacking Isshin was so that his organ could be harvested (Isshin is a registered organ donor) and used to save his daughter. Yakumo managed to corner Sakaibara on the hospital heli-pad. Gotou, Ishii, Haruka, Nao and Makoto arrives shortly after. (thetvdb.com)