Go into the Kurosawa House on the first floor. Go into the Great Hall (where you first encounter Sae Kurosawa and the Kusabi). Make sure you have Mayu with you. Have Mio stand in front of Mayu, face-to-face, and pull up your camera. Take a picture of Mayu and bloody hands should be surrounding Mayu in the picture. Note: This event only happens in the Great Hall. If you take any other pictures of Mayu in other room, then those bloody hands will not appear.