Wow, look at all the money! You can't take it, but you can right-click to look at it more closely. What the heck is GCT? Using Oogle is no help without more information.
Hint 5
Once Rosa opens the locked door and talks to Ryan --
Click on "GCT" and "Bank" to have Rosa combine the two ideas. She comes up with the name of a bank, the Grant City Trust. Look that name up in Oogle to get Ryan's whole story, which you can confirm by talking to him about it.