"Hmm, this is weird. Looking at the condition of Cao Keya's parents' house, although it has three bedrooms and is located in a satisfactory location, it's actually a relatively old building. It's one of the houses divided from units about twenty years ago when the area was not well-developed and had low housing prices. According to my investigation, Cao Keya's parents owned no other property besides this one.

"According to Cao Keya's parents, there have been rumors spreading around their neighborhood that the houses there are going to be demolished. Thus, the Cao family is waiting for compensation from the government. With that money, they can buy at least two new houses in other areas. Looking at the situation, the Cao family is not all that well off. Her father is a construction worker and her mother has retired with a low pension of two thousand and five hundred RMB a month. Money is quite tight for their family. Despite that, Cao Keya could live in a house with three bedrooms and two living halls. Moreover, the area she lived in is considered mid-to-high range."

From the moment the body was found in the bathtub, Qi Youxuan knew that Cao Keya lived in quite a luxurious house.

"You can look into her personal life. She could be just like our first victim, Xiong Shishi, who came from a middle-class family but found a rich lover to improve her life."

Yang Shaoqun, along with Wei Muran and Yang Shaozhan who were in the same office, heard Qi Youxuan's words over the phone and their lips all twitched at the same time.

To improve her life…

What an implicit yet accurate way to put it.

"Based on the MO, we can conclude that this is the work of the same murderer. The only thing is he's upping his game," Qi Youxuan deduced.

Yang Shaoqun let out a sigh of relief over the phone. "The truth is, I had hoped for it to be the same murderer. Although serial killers are absolutely detestable, at least they only have one motive, and we won't have to run down two separate roads. Hearing you say that brings such relief to me."

"Mmhmm." Qi Youxuan agreed with him on this. "When two murder cases happen within such short intervals, there's very low chances of it being unrelated. Although his methods had improved this time around, the style is still the same—it has to be the same guy. Just like an old building, at first, the walls look tattered and torn, but after putting on a fresh coat of paint and painting on a beautiful mural, it appears much more elegant than before. Nevertheless, only it's outer appearance changed. In reality, they're still the same tattered and worn cement walls."

"Then how did you know to check Cao Keya's personal life first?" Yang Shaoqun inquired.

Yang Shaoqun put a hundred percent trust in Qi Youxuan's predictions—he would follow them blindly anywhere. He merely asked this question to learn more from Qi Youxuan, which would benefit in future cases.

"Does Xiong Shishi and Cao Keya know each other? Are there any relations between the two victims?" Qi Youxuan asked instead of answering.

"No," Yang Shaoqun replied.

"The two of them had no relations, yet they were murdered by the same person. Or they could simply be killed for the same reason. The three of them may not know each other, but the two women may coincidentally fit the murderer's 'victim profile'. Serial killers will always kill based on a certain criteria. His victims all fit this profile. Some kill simply based on the color of garments they were wearing or the style of clothes; some may kill based on the people their victims associate with or based on certain habits of their victims," Qi Youxuan expounded.

"Cao Keya came from a middle-class family. She was a nurse, so her salary was not that high either. Even if she rented instead of buying this house, there was no way she could afford it. That's why I want you to look into her personal life—whether she had a shady relationship with a man just like Xiong Shishi. Look into the owner of this house, or find out who's renting it for her," Qi Youxuan instructed.

Yang Shaoqun showered Qi Youxuan with compliments over the phone. His admiration for him ran deep.

Naturally, Qi Youxuan would not reveal that the main reason he could make all those deductions because of the novel 'Killer of the Heart'. The third case in the book was also a serial murder. Although the murderer had a different motive than the one in the novel, both murderers had specific criteria when it came to choosing their victims.

Based on that simple concept, it was possible to deduct that what tied Xiong Shishi and Cao Keya's cases together was the fact that both victims had a secret lover.

However, Qi Youxuan was afraid that Yang Shaoqun would not believe in theories derived from a crime novel.

"Have you heard of the novel 'Killer of the Heart'?" Qi Youxuan finally asked.

Yang Shaoqun was perplexed. He felt that he could not keep up with Qi Youxuan's racing thoughts.

Was this what was known as the IQ gap?

"No, I haven't. Why?" the confused Yang Shaoqun inquired.

"The book can help you in your investigations. You should check it out," Qi Youxuan advised.

If nothing out of the ordinary occurred, these three cases would be closely similar to the ones in the book. It would definitely benefit Yang Shaoqun if he read the novel during the investigation.

Only after he finished the book would Qi Youxuan reveal to him how the cases in the book were connected to the cases they have. That way, Yang Shaoqun might be able to accept his deduction methods better.

Despite only spending a short time with him, Qi Youxuan believed that Sergeant Yang seemed to be quite open to new concepts.

Yang Shaoqun's first reaction was to ask, "Is this an essential reading material in criminology?"

"..." Qi Youxuan started to wonder if Yang Shaoqun was promoted to sergeant solely due to his wild imagination. "Just read it, then you'll know."

"Umm…" Yang Shaoqun hesitated. "Mr. Qi, can you come over to aid us?"

"I'll be there as soon as possible," Qi Youxuan replied. He decided to check if Jiang Yuecheng could apply to go down to T City with him for this case; otherwise, he would have to go alone.

Nonetheless, he had started to develop an interest in this case.

In the beginning, he took up criminal psychology for the sake of Wei Muran. However, as he dived deeper into the field, he fell in love with it. Despite specializing in acting cute to get what he wanted when he was a child, Qi Youxuan was actually incredibly intelligent. After all, he had the Qi family's exceptional genes.

He learned things at lightning speed, making everything boring for him.

When he worked in Qilin, he welcomed challenges with open arms. He enjoyed solving problems that stimulated his mind, coming up with new technologies and improving their products year after year.

Moreover, he adored solving these mind-bending cases—it was like solving riddles. It was something that he would never find tedious. When working on the case, he was fuelled with energy and when it was finally solved, not only would he feel relieved, he would also feel a strong sense of accomplishment and satisfaction.

Hence, the more he learned about the case, the more entranced he became. Qi Youxuan was more than willing to take on the challenge. He craved the mental stimulation.

Yang Shaoqun was in disbelief. Qi Youxuan actually said yes? Exhilarated, Yang Shaoqun stuttered, "R-r-r-r-really? M-m-mister… Mr. Qi…"

"Calm down," Qi Youxuan quickly reminded. He had to repeat this several times before Yang Shaoqun could collect himself.

"Ah, I'll stop talking now. I… I'll dig out all her relations, gather information, and record testimonies right now. When you, Great Master, arrive, I'll hand you all that I've compiled and we can crack this case in no time!" Having said that, Yang Shaoqun hung up.

Qi Youxuan stared at his phone in silence. Yang Shaoqun was quite creative too; how did he start from calling him Mr. Qi to 'Great Master'?

…

Meanwhile, Jiang Yuecheng was in the chief of department's office requesting permission to head down to T City to help with the case. The chief sighed loudly. Evidently, he was troubled by his request and did not seem willing to grant him permission.

"Yuecheng, how should I put this? You see, this is not something I can decide on alone. I need to discuss with the folks down in T City and only when they agree, will you be able to go. But what reasoning should I give them? Tell them about this novel you read? Who would believe in something so far-fetched?" the chief explained, shaking his head.

"Not only are you determining the nature of a crime according to a novel, you want jurisdiction over another department's case? Don't you think that's too inappropriate? Do you think this is a joke?"

"Chief, I've explained everything in detail just now. The facts are all here," Jiang Yuecheng countered patiently. "The first time may be by chance, the second, a coincidence, but what about the third? Besides the motive, everything else about these cases is similar—the MO, the outcome et cetera. Or perhaps you think that three killers read the same book, held a meeting and decided to kill three people in the exact same sequence as in the book? You'll mimic the first case, I, the second, and him the third?" he rationalized.

The chief's expression darkened. Jiang Yuecheng was practically mocking him.

"The third case hasn't been confirmed, right?" the chief reminded.

"It'll be too late by the time they confirm it. If the third case is exactly the same as the scene from the book, will you finally believe me? Even so, by then, it would be too late. How will we find the man behind all these murders? By then, we would be two steps behind. Or do you wish to wait until the fourth case emerges? This is our chance, Chief. Before more bodies appear, we have to find this murderer. We can't sacrifice any more innocent civilians."