A very short game with a little secret!
My suggestion for improvement is that you can add these mechanics:
1) Expand the Q key mechanic. Make arresting the wrong person more significant. For example, you can punish the player for arresting the wrong person - change the murder colours, let the player not restart the game, but change the investigation.
2) Also, add more people and make some innocent people lie. This will make the investigation more difficult.
But it's a nice try for a mini-game made for a mini jam!