Secret Hide-away Box

The scene: A museum in Grand Rapids, Michigan.  Someone has stolen rare and precious artifacts from a jewelry exhibit.  Detectives believe that after the heist, thieves may have stowed away the treasures somewhere in the desk of this office space.   Can you find their secret hiding place?
I'll give you a hint: You'll get a hoot out of this hiding spot.

Secret Book Safe (DIY)

I have always wanted to make one of these!