You time traveled to the time before 15 minutes of when Ai Hoshino got murdered. You went to the house where Aqua told you. That was the house Ai , Aqua and Ruby lived.

You looked through the window. You saw small aqua in the bedroom sitting in the bed and Ai Hoshino, his mother combing her hair.

You can knock the door or can stay quiet and wait for the killer instead.

13 minutes remaining before the killer comes