INVESTIGATE CAFé ALPS
Open the Buzz Researcher and search for Office Alone 4 or robbery.
It won't work if you just show up at the Café Alps.
Enter Observation Mode and investigate the sign at the door. Turn it around and investigate the SOS.
HEAD TO THE BACK OF CAFé ALPS
You will get there in a cutscene.
Lockpick the back door.
FIND A WAY TO APPROACH THE ROBBER.
There is a light blue arrow pointing to a ONO costume. Put it on and sneak in.
Now look at the cart boxes with the blue arrow.
Hide in a box and sneak in.
Now play "Red Light, Green Light" with the box. Move it closer to him while he's not watching.
Chase after the burglar.
Reward: Extract Recipe: Snake Bomb Tactic