On Kitz's body, traces of iodine-carbon arsenic were found. It's not yet clear what it could have been used for... On the scene, near the body, there was an inscription: "As my friend says: 'To be or not to be'."
In the pocket of the deceased, documents were found in the name of H. Hefnerova.
Arsenic, the inscription, and the documents are clues pointing to the role of the killer, the victim, and the evidence.
What and where, I still don't quite understand.
Tengro was killed in a completely different way. His chest was torn open by a shot from something large-caliber (the weapon is being identified), and a shuriken was deeply embedded at the base of his neck. Interestingly, it was possible to establish that Tengro himself was a fan of such things.
This is more interesting.
Tengro is an assassin; there's no question about that, in my opinion.
And he was killed by two people.
He was shot either by bandits or a devourer. Most likely, by bandits, as they have a more powerful weapon.
In addition, an illusionist used the Non-Detect spell on Tengro himself, which is why there is no evidence of his murder (1 - the assassination of the assassin occurred before all the others; 2 - no evidence is given for him). That is, they were shooting at Tengro after he was already dead.