Thank you for trying!
The goal of the book is to match the face and name of all the people of the story.
When you're done with this step, you can try and guess the culprit.
If I had more time, I would have added tips from the policeman, sorry :(
The concierge says something that helps you know who lives in which appartment, and then on each appartment door if you click you get a hint of the names of their inhabitants. I hope that helps enough to get you un-stuck :pray:
I played your game by the way, loved the funky artstyle, well done!