Мафия 9. Mage Valley

slime and mollusks - maybe an indication of a Warlock (see avatar), who came after the killer? If so, what was the alchemist's purpose? Did he hope for a 30% chance to kill a potential Mafia member, or did he believe in his innocence and want to protect him?

The painted walls - is it art, paintings? But is it a clue?