More clues

Kaj's deductions - though excellent and sharp-witted - were based on so called circumstantial evidence. That is hardly admissably in a court of law. Such evidence is too easy to plant to mean anything. What's a matchbox or a napkin? Did you notice how they were placed in the picture? Just as they would be if they were real, weren't they? A good setup aims to be exactly correct. When you think about it, wasn't the setup perhaps a little too perfect? The napkin only half-visible, the matchbox barely in view?

Here are a few more clues:

Princess Elizabeth was married to the guy with the magnificent beard until she was brutally murdered.

This city is historic, as shown by the following pictures of its traffic:
Even Helsinki doesn't have trams this old!
Is there a clue in this picture? The language is German, sure.
Who writes like this?
A huge palace, no longer used for governing.