Thanks for giving it a go!
Ya, its a odd game, basically you play as a very incompetent detective, so some things that should be suspicious are not and so on :P It's also meant to be very easy, as I wanted character cards you could solve, but I only managed to finish one right now.
Clues can be found on the card, with the 3 interaction buttons, the one you missed was just talking to him I think.