So, regarding the first murder of Gura, we have the method of his death, footprints, bear paws/claws, a scratched inscription on the wall with a counting rhyme, and a seal that likely belonged to the victim – both Revan and Hostor seem to fit, but I don't know what the counting rhyme has to do with it and how it points to Hostor... maybe it means that it's a child's rhyme, and he's the youngest of us in terms of forum tenure! Although, having two clues for the same murder... nevertheless, one of them could be the truth.
Now, regarding the murder of Kostyan – a magical artifact-watch, awakening its owner at 8 AM (???) and a strange death – upside down and severely aged... and again, Revan and Hostor have watches/time in their signatures...
As far as I know, bats usually sleep upside down, vampires tend to turn into bats, and premature aging is sudden, instantly aging by several hundred years, as if someone drained the life out of him, you could say they dried him out... Cash has a link to a vampire clan in his profile; also, his "hoochie Coochie Man" – in the song by Chizh & Co. (the title of the first night is reminiscent of "Night Musician") there are the following lines:
"Oh, I'm Hoochie Coochie, oh, I'm Hoochie Coochie Man
Roll my body, mama: I'm completely dehydrated." - could it be a coincidence?))
In general, I'm still thinking...