Hello!
Glad you enjoyed the game.
There should be 6 or more valid evidence in order to enable that event where you write the name of the suspect.
There are different endings in the game, and to fully understand and get the "Write the Suspect" Route, you'll have to finish the other ending first.
To use Full Screen, press Alt+Enter/Return.
Please take note that it is also Case sensitive. ;)
Have a good day!