"Mass hysteria?" Sir Devill, who had been in contact with quite a number of psychologists recently, mulled over the term Klein used.
His butler, bodyguards, and servants did not make a sound without his permission, no matter how curious they were.
Sheriff Gate, on the other hand, looked at Klein with doubt, showing no sign of having heard of such a concept before.
Klein controlled the habit of tapping the sofa armrest with his finger and explained in a low, soothing voice:
"Humans are creatures easily deceived by their own senses. Mass hysteria is a psychogenic problem caused by factors like mental stress influencing each other within the same group."
His series of technical terms confused Sir Devill and Sheriff Gate, making them instinctively believe him.
"Let me give you a simple example. It's a case I once handled. A gentleman hosted a dinner party and invited thirty-five guests. At the dinner, he suddenly felt nauseous and vomited on the spot. Later, he had severe diarrhea, once, twice, thrice. He began to think he had food poisoning, and while heading to the hospital, he told his guests about this guess."
"In the next two hours, over thirty of the thirty-five guests had diarrhea, and twenty-six vomited. They packed the hospital's emergency room."
"The doctors conducted detailed examinations and comparisons and concluded that the gentleman hadn't been poisoned at all. The cause was gastroenteritis brought on by a combination of weather changes and cold spirits."
"What was most surprising was that none of the guests who came to the hospital had been poisoned, and in fact, none of them were actually sick."
"This is mass hysteria."
Sir Devill nodded slightly and praised:
"I understand. Humans are indeed prone to deceiving themselves. No wonder Emperor Roselle said that a lie repeated a hundred times becomes the truth."
"Officer, how should I address you? You are the most professional psychologist I have ever met."
"Inspector Moretti." Klein pointed to his epaulet. "Sir, your problem has been temporarily resolved. You can try to sleep now, so I can confirm if there are any other issues. If you can have a good dream, please allow us to take our leave early and not wait for you to wake up."
"Alright." Devill rubbed his forehead, picked up his cane, and went upstairs step by step into the bedroom.
Half an hour later, a police-emblazoned carriage left the fountain in front of Sir Devill's mansion.
After Sheriff Gate got off midway to return to his station, Inspector Toller looked at Klein and said, half-flatteringly and half-jokingly:
"I almost thought you were a real psychology expert just now..."
He didn't finish his sentence because he saw that the young man in the black and white plaid uniform showed almost no expression. His eyes were deep and dark, and his mouth twitched slightly as he said:
"I just came into contact with some of it in the past."
Inspector Toller fell silent until the carriage stopped outside 36 Zouteland Street.
"Thank you for your help. Sir Devill is finally free from his troubles and has regained his sleep." He reached out and shook Klein's hand. "Give my thanks to Dunn."
Klein nodded slightly:
"Okay."
He walked up the stairs, step by step, back to the Blackthorn Security Company, knocked, and entered the Captain's office.
"Solved?" Dunn was waiting for his lunch.
"Solved." Klein rubbed his forehead and said concisely and truthfully, "The root of the problem lies in the lead and porcelain factories under Sir Devill's name. Since their establishment, there have been too many deaths from lead poisoning, and each incident caused Sir Devill to absorb a bit of resentment left over from residual spirituality."
"Normally, these wouldn't cause major problems, just make one prone to nightmares." Dunn had handled similar cases and was quite experienced.
Klein nodded slightly: "Yes, that's how things were supposed to go. But unfortunately, Sir Devill met a female worker suffering from lead poisoning on the street one day. She happened to fall by the roadside, also happened to see the Devill family crest, and at the same time, she had strong feelings of unwillingness, worry, and longing. Only when the knight gave her parents, brother, and sister a compensation of 300 pounds did these emotions dissipate."
"This is a social issue, not uncommon in this age of steam and machinery." Dunn took out his pipe, sniffed it, and sighed. "Flax workers, because they get the materials wet and themselves wet in the process, commonly suffer from bronchitis and joint diseases. In factories with heavy dust, even without poisoning, lung problems will accumulate... Hah, let's not discuss this. With the development of the kingdom, I believe it will all be solved. Klein, tonight, let's find a restaurant to celebrate you becoming a full member."
Klein thought for a moment: "Tomorrow night... Captain, I used my spiritual vision for too long today and directly communicated with those resentments using the 'dream divination' technique. I feel very tired. I hope I can go home this afternoon and rest well. Is that okay? Yes, I'll go to the Divination Club around four or five to observe the members' reactions to Hainas Vansen's sudden death."
"No problem, it's fine." Dunn laughed. "Tomorrow night at the old Weir's Restaurant next door. I'll have Rozanne book a table."
Klein stood up holding his police cap, bowed: "Thank you, Captain. See you tomorrow."
Dunn raised his hand: "Wait, you said Sir Devill gave the female worker's parents 300 pounds in compensation?"