I tend to think that neither Lizard nor his killer is a member of the Black Death, otherwise there would be references to it. For myself, I accept the version that Lizard was a vagrant, and he was killed by an ordinary gangster, as the most plausible and in the absence of perfectly substantiated options.
And about the shout, it is also possible to come up with a thousand theories. We can assume that the killer knew Lizard and called him by name, or we can imagine the shout as a simple "Hey, you!" and kill the preceding half-hour searches for possible acquaintances of the victims and the killer.
Can the shout be a clue?
Наше оружие - неожиданность! Неожиданность и страх, страх и неожиданность - это два наших оружия! Плюс безжалостность - три наших оружия: страх, неожиданность и безжалостность! И ещё фанатичная преданность Папе - четвёртое! Наше оружие включает в себя... наше оружие включает в себя... страх, неожиданность... я сейчас!



