As for the night, then
Sub Zero and Zubr were found to be under the observation of two people.
Sandro was behaving strangely. And no one saw Rudyi.
Neira Drake received a rose-scented letter from a secret admirer.
A person of an unreliable appearance was loitering by Wolfstet's tombstone.
Amko was stabbed in an alleyway. Such a fate was more deserved by street scum than him. However, those who might know the nature of his occupation would even agree that this fits Amko as well. The deceased offered almost no resistance, for he had always relied on mental rather than physical abilities. This even slightly disappointed the killer, who was used to a struggle. Leaving the crime scene, he didn't notice how he dropped 100 pieces of paper with "54.08.30." written on them.
Clue - "Leaving the crime scene, he didn't notice how he dropped 100 pieces of paper with "54.08.30." written on them."
Rudyi was sleeping peacefully in his bed when he was killed. The man with the crazed look didn't care about any of the moral virtues of his victim. With a beastly smile, the killer left Rudyi's dwelling, where the atmosphere after the master's death resembled the year of the 34th Father's passing.
I'll check the connections now

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!