Where to get this case:
The case starts with that weird "Noise" in the Buzz App at the walkway near the river right below Seiryo High.
The detector leads you to the entrance door of the high school.
TRACK THE SIGNAL SOURCE IN SEIRYO HIGH
Enter the High School.
The Target is one of the Soda Machines in the cafeteria. Right next to the shop.
Take out the Detector again.
The next camera is inside the Gymnasium on one of the green pillars on the wall, right at the power slot.
Next, go to the Dance Club in the basement and use the Detector on the cart boxes on the wall.
Next, go the second floor Hallway. There are some lockers at the west end. The signal is coming from locker 12.
Pick the lock.
Next, go the MRC Room. The signal is coming from the door.
Enter the MRC and use the detector on the cables on the ceiling.
The culprit is... the custodian.