“Director, we investigated with the electric company and found out clearly—Zhou Qi’s home had a sudden spike in electricity usage the day before yesterday, which means the air conditioning was only turned on the day before yesterday. The timing was right before Lang Botu came to the Public Security Bureau.” The next day, in the office, everyone gathered around Zhang Yi’ang to inform him of the latest investigation results.

According to Medical Examiner Chen’s analysis, Lang Botu’s scheme was extremely vicious.

Zhou Qi’s home was renovated last year with smart air conditioning that could be remotely controlled by phone—most likely Lang Botu learned about this when they chatted. Lang Botu probably came to Zhou Qi’s home on the daytime of November 5th, killed Zhou Qi, and took her phone and the key to Lu Yibo’s office. He then killed Lu Yibo that evening and subsequently infiltrated Lu Yibo’s office to take some documents. At the same time, he installed surveillance at both Zhou Qi’s home and Lu Yibo’s office for the purpose of monitoring the police investigation’s progress.

On November 6th, Lang Botu went on a business trip to Beijing. Two days later, he returned to San Jiang Kou and deliberately used a virtual phone number with a voice changer to make an emergency call, informing them of Lu Yibo’s corpse location. After the police discovered the corpse, naturally they would investigate his interpersonal relationships. If the police investigated and found that Zhou Qi was Lu Yibo’s girlfriend, they would go to her home. After seeing through the door surveillance that someone had arrived, he would use his phone to remotely control the air conditioning to maximum temperature. Because this wasn’t arresting a criminal, the police wouldn’t directly break down the door—by the time they got keys, found family members, and completed this series of tasks before entering the room, the entire room would already be heated up by the central air conditioning. If the police didn’t discover Zhou Qi was Lu Yibo’s girlfriend, he would definitely make another anonymous phone call to report it, having the police find Zhou Qi’s home in time.

So when he was summoned by the police bureau, he first used Zhou Qi’s phone to turn on her home’s air conditioning. After arriving at the police bureau, he deliberately revealed during the conversation that Zhou Qi was Lu Yibo’s girlfriend, luring the police to investigate at Zhou Qi’s home and discover the corpse in the air-conditioned room.

According to Lang Botu’s original plan, after the police found Zhou Qi’s corpse and discovered the central air conditioning turned to maximum temperature, the medical examiner would believe the environmental temperature was too high, causing accelerated decomposition, thus determining her time of death to be shorter—meaning they would conclude Zhou Qi died after Lu Yibo. And after Lu Yibo’s death, Lang Botu had a full two days of alibi. Even if the police investigated him, they would directly rule him out as a suspect based on his alibi.

According to Medical Examiner Chen’s explanation, if Lang Botu had turned on the air conditioning directly after killing Zhou Qi, both the environment and the corpse’s degree of decomposition would have changed—with both factors changed, an experienced medical examiner like him wouldn’t make an error in determining time of death. Only by changing this single environmental factor close to when the corpse was discovered could it mislead the medical examiner’s judgment of time of death to be shortened.

This scheme was extremely vicious—Medical Examiner Chen’s lifelong reputation had nearly been tarnished in his later years. After figuring it out, he actually thanked Song Xing. Lang Botu had turned on the air conditioning all night, but before the autopsy Song Xing turned it off, causing the autopsy results to actually be longer than reality. Two negatives made a positive—Lang Botu’s conspiracy backfired, which is what caused him to lose his temper in shame and blurt out his questioning of Medical Examiner Chen’s professional competence.

Those who questioned Medical Examiner Chen’s professional competence never had good endings. Lang Botu was the best example—see, didn’t he expose himself?

Lang Botu’s conspiracy was figured out, but the current problem was lack of evidence—no physical evidence whatsoever. Lang Botu stubbornly insisted the murder case had nothing to do with him. How could they convict him? The police all knew now that he was the killer, but the legal level didn’t support it.

At this moment, Li Qian pushed open the door and walked in cheerfully, carrying a transparent plastic bag in her hand with a phone inside.

“Director, Zhou Qi’s phone has been found. Lang Botu can be convicted.”

Zhang Yi’ang stood up abruptly with his crutch: “Excellent!”

Everyone was puzzled about how Li Qian had found Zhou Qi’s phone.

Zhang Yi’ang took the bag and headed straight to the interrogation room, having someone arrange to interrogate Lang Botu again. At the same time, he instructed Song Xing to arrange two teams—one to go to Lang Botu’s home, one to go to Lang Botu’s company, waiting for his order to search at any moment.

After Lang Botu was seated, Zhang Yi’ang immediately pulled out the evidence bag and sneered at him: “Lang Botu, look carefully—whose phone is this?”

Lang Botu stared at the phone for several seconds, and his expression immediately changed dramatically: “This… this is impossible.”

“How is it impossible? Yesterday before we summoned you, you turned off Zhou Qi’s phone at your company and threw it away. We searched everywhere, and finally your company’s cleaning staff picked up the phone and turned it in.”

Lang Botu bit his teeth with a strange expression: “So that’s how it was.”

“Then tell me, where did you hide the other murder weapons like the knife blades?”

Lang Botu thought for a few seconds and said: “They’re all in my home garage—I dismantled them and tossed them aside.”

The people in the interrogation room and behind the monitors collectively let out a cheer—the case had finally come to light!

“You’ve finally confessed—not easy,” Zhang Yi’ang laughed heartily. “Actually, I was deceiving you. This isn’t Zhou Qi’s phone at all. After I found out clearly what phone Zhou Qi used, I had someone borrow a second-hand one.”

Everyone was stunned—they were all thinking Director Zhang’s move was too brilliant, forcibly tricking him into confessing.

Before everyone could finish celebrating, Lang Botu also laughed heartily: “Actually I was deceiving you too. There’s no murder weapon at all in my garage. I didn’t kill anyone at all. Search all you want.”

Everyone was stunned again, staring blankly at Director Zhang. How would this play out now? He knew the police had tricked him—they probably couldn’t interrogate out where the physical evidence was hidden anymore.

Who knew Zhang Yi’ang would continue laughing heartily: “I never expected this trick to make you come completely clean. I was just testing you to verify a conclusion.”

Lang Botu paused for several seconds, suddenly had a very bad premonition, his expression changed dramatically, he swallowed heavily, and slowly asked: “What did you want to verify?”

“The day before yesterday, before summoning you to the Public Security Bureau, my people were stationed all around your company. Before you came, you turned off Zhou Qi’s phone, which means at that time Zhou Qi’s phone was still at your company. After that you came to the Public Security Bureau and never had a chance to go out again. I was thinking—where would this phone be? One possibility—you threw the phone in a trash can at the company and it was carried away with the garbage. But when I just said it was picked up by cleaning staff, you said it was impossible. Then the only possibility is that the phone is still hidden somewhere in your company! As long as this point is confirmed, no matter how small the phone is, if we invest enough manpower and spend enough time, we’ll definitely be able to find the phone in your company!”

After these words were spoken, Lang Botu’s face immediately turned ashen, all hope lost. After several seconds, his body completely collapsed, slumping limply against the interrogation chair, the light gone from his eyes.

“Now I’m giving you a chance. If you readily tell us where the phone is hidden, saving so many of us the effort of searching, then after you enter prison, I’ll also instruct the prison guards to treat you more courteously. But if you remain stubborn and we have to turn your company upside down with so many people before finding the phone, then I don’t need to say more—all these people working overtime isn’t tiring? How about after you’re in prison we arrange for you to room with a bunch of rapists? Look at you, this pampered young master with delicate skin and tender flesh—you should be quite popular, right?”

Hearing these words, Lang Botu’s entire body trembled, his voice shaking as he said: “The phone… the phone is in the air conditioning vent above the adjacent Vice President’s office. The murder weapon… the murder weapon is knife blades installed on a modified board. I threw them all in the river—the river north of my home. I’ll cooperate with you to find them.”

Zhang Yi’ang chuckled lightly and immediately called the police waiting outside Lang Botu’s company, having them search for the phone in the air conditioning vent of the Vice President’s office. In just five minutes, good news came—Zhou Qi’s phone was found. Now with both confession and physical evidence complete, Lang Botu could never escape even with wings.

All the criminal police let out cheers—this operation of tricking him, being counter-tricked, then tricking him again to finally get results was simply textbook interrogation technique! Everyone completely surrendered to Director Zhang’s investigative artistry.

Zhang Yi’ang finally relaxed, smiled at Lang Botu: “For the rest, cooperate with the interrogation and suffer less. I don’t need to explain the policies—do what’s best for yourself.”

“Wait—” Lang Botu raised his head weakly and called out to him, asking unwillingly: “My plan was so thorough—what was the reason? Why did you lock onto me when you had no evidence at all? Why did you insist on suspecting me?”

Yes, why did Director Zhang determine from the beginning that it was Lang Botu? Even when others had differing opinions, Director Zhang always believed without doubt that Lang Botu was the killer. Could it be because of that segment in the recording that Director Zhang settled a personal grudge and happened to stumble onto the truth?

Zhang Yi’ang smiled slightly, sat back down, looked at him calmly and composedly, and said: “Because of your excessive cleverness.”

“I… I was excessively clever?” Lang Botu looked at him bewildered.

“After Lu Yibo died, I saw two photos in the drawer of his office. Combined with investigating some past events, I quickly figured out your motive for the crime.”

“You… you know my motive?”

Zhang Yi’ang sighed: “Many parents don’t understand how to treat their children equally, leading to countless tragedies. Take your family for example—from childhood your parents favored you, the younger son. Even the factory was named after you—Aotu, not Aowen. After your father died, your mother transferred the entire factory to your name without your brother’s share. He could only leave to do business with Zhou Rong. You didn’t cherish it well—ran it carelessly, spent recklessly. After a few years, the factory was nearly bankrupt. At this time, an employee happened to report you for fraudulently obtaining state tax rebates. Not only were you fined, the police arrested you—it was Ye Jian who personally arrested you then. Later the factory was sold, and your brother Lang Bowen and Zhou Rong took it over, got the factory operating back on track, and kicked you out. After being released, you figured it out—this was clearly a setup. Your brother Lang Bowen, together with Zhou Rong, Ye Jian, and Lu Yibo, set you up with the purpose of taking back the factory your parents left solely to you. Of course you were angry inside, but on the surface you had to be grateful to your brother. From then on, you could only live with your head lowered under his wing. Watching him and Zhou Rong’s business grow bigger and bigger, your heart became even more unbalanced, so you began planning revenge. Zhou Rong—you had no ability to make a move against him. You could only start with the easiest targets. The easiest to kill was naturally Ye Jian. Although he was a criminal police officer, he always acted alone. At a dinner gathering you secretly left him a note, probably writing something that could pique his interest, arranging to meet him by the lake to kill him. After killing him, you waited a long time—the police didn’t even come to talk with you. You became more confident about killing, so you killed Lu Yibo and Zhou Qi. Also, regarding Lang Bowen—he’s missing now, but perhaps not really. Maybe you already killed him too.”

“What are you saying?” Lang Botu straightened his body.

Zhang Yi’ang spread his hands: “This is just my speculation. Without discovering his corpse, I can’t draw conclusions. You killing him while Zhou Rong was in trouble would be perfect—we’d also suspect he fled in fear of punishment. I can only say you did it very cleverly. Especially deliberately fabricating the crime scene at Zhou Qi’s home, you almost misled our determination of time of death, giving you an alibi. However, your luck was really bad—you encountered me. You shouldn’t have, absolutely shouldn’t have written my name at Ye Jian’s death scene, trying to frame me.”

“I wrote your name at Ye Jian’s death scene?” Lang Botu’s eyes widened.

“Yes, and you even more shouldn’t have, after killing Ye Jian and Lu Yibo, left those two old group photos—that was superfluous. This criminal psychology is very common—it’s a kind of pleasure from revenge. Look, the old grudge was finally avenged. But this was really unnecessary. Your intelligence is very high, the setup was beautiful, but all high-intelligence criminals have a fatal problem—they always like to show off during the crime.”

“I… I left two group photos?”

Zhang Yi’ang looked at his reaction strangely: “Wasn’t it you?”

“You… what are you talking about? It’s not at all what you’re saying!” Lang Botu’s entire face filled with blood as he shouted emotionally: “Don’t you know about the accusation letter!”

“Accusation letter?”

“Ye Jian wrote an anonymous accusation letter to Gao Dong, accusing Zhou Rong of killing Lu Zheng to silence him!”

Zhang Yi’ang immediately recalled the reason for his coming to San Jiang Kou—the anonymous accuser was Ye Jian? He asked hesitantly: “That letter was written by Ye Jian?”

Lang Botu shouted angrily: “Of course it was written by Ye Jian. Lu Zheng was tracking Luo Ziyue and discovered his relationship with Zhou Rong. Zhou Rong sent people to kill Lu Zheng and dump his body in the river. Ye Jian suspected Lu Zheng’s disappearance was related to Zhou Rong, so he kept investigating secretly. He even got Lu Yibo to turn against him and wrote an anonymous accusation letter to Gao Dong.”

“How do you know about this letter?” Zhang Yi’ang knew the accusation letter was given to Gao Dong—Zhou Weidong didn’t know about the letter’s existence, much less Zhou Rong’s group.

“Because I discovered a bug in my brother’s car!” Lang Botu said coldly. “I investigated privately and believed the person most suspicious and capable of doing this was Lu Yibo, so I confronted him face-to-face. Unable to withstand my interrogation, he admitted that Ye Jian wanted him to cooperate in investigating Zhou Rong, advising him not to follow Zhou Rong anymore lest he sink deeper. He also said Ye Jian wrote an anonymous accusation letter to Gao Dong, and Gao Dong would send people to investigate. So during that dinner I deliberately left a note for Ye Jian, hinting ‘I know the answer you want,’ arranging to meet him by the river and taking the opportunity to kill him to silence him. At that time, so many knives on the front of the car stabbed into Ye Jian, yet he didn’t die on the spot—he actually jumped into the river and swam away. I watched from afar as he swam to the opposite bank and died. That place was all muddy ground—I didn’t dare go over and leave footprints. I never walked up to him—how could I possibly have left any words!”

Zhang Yi’ang was stunned. In an instant, he understood everything. Ye Jian was a good person. Before dying, he realized the accusation letter matter had been exposed and the other party wanted to kill to silence him. He deliberately took out the spa card to remind the police—quickly go find Lu Yibo. He wrote Zhang Yi’ang’s name with an exclamation mark to hint to Zhang Yi’ang—the accuser you’re looking for is him, and everything from here on was entrusted entirely to Zhang Yi’ang! Before dying, Ye Jian endured severe pain and painstakingly made two hints, yet Zhang Yi’ang hadn’t understood either one.

Lang Botu looked at him huffily and continued: “After Ye Jian was killed, Lu Yibo probably knew I did it, but he didn’t dare say much. I observed him and Zhou Qi for a long time—I felt they were both ticking time bombs. That day when Zhou Rong’s flash drive was taken by someone, my brother, fearing he couldn’t resolve the matter and would be implicated, left San Jiang Kou first. I then killed Zhou Qi and Lu Yibo, and took and destroyed some private account materials from his company to eliminate future troubles. What you’re saying doesn’t exist at all. When I was young I was foolish and squandered my parents’ life’s work. My brother saved the factory back—I’m grateful before it’s too late! I killed people to protect my brother—how could it be because I resented him! Also, my parents treated us two brothers equally. The factory was given to me because my brother didn’t want it—he was given money to do business. The factory being called Aotu has nothing to do with my name at all. Aotu in English is Auto, meaning automobile. Isn’t it normal for an auto parts factory to be called this name!”

An interrogator slapped the table and shouted: “Complete nonsense! The English word for automobile is Car. Do you think we police don’t understand English?”

Lang Botu let out a cold “heh heh” laugh. The other interrogator beside him quietly reminded his colleague—Auto also means automobile.

Zhang Yi’ang coughed and asked: “Then why are there photos with dates written by you in both Ye Jian’s home and Lu Yibo’s office? Why did your expression change dramatically when you saw those two photos?”

Lang Botu roared: “Each of us has this photo. Isn’t it normal for Ye Jian to keep it at home? How should I know why Lu Yibo kept it in his office! The dates were written because later we discovered the anniversary date wasn’t written—my handwriting is good so they asked me to mark it. What’s wrong with that! I was nervous because I thought you’d discovered the true relationship between the several of us and knew my motive! Who would have thought you knew nothing—you knew nothing at all, yet you still interrogated a confession out of me. I—” With a “poof,” Lang Botu actually spat out a mouthful of fresh blood.

All the police officers behind the monitors froze completely.

If they had understood Ye Jian’s hints from the beginning, they wouldn’t have investigated the spa, and without investigating the spa they wouldn’t have investigated Zheng Yongbing, wouldn’t have discovered Liu Bei at his home, wouldn’t have caused Liu Bei to flee. If Liu Bei hadn’t fled, he wouldn’t have taken the risk to steal the bronze bells, and everything that followed would have been rewritten.

The source of all this was because both hints Ye Jian left before dying were misinterpreted?

But the initial hypothesis was wrong, even their entire investigation direction was wrong, even the autopsy process had errors—so why, despite being wrong from start to finish, did they still catch this carefully planned high-intelligence criminal?

Everyone’s gazes awkwardly turned toward Zhang Yi’ang.

Zhang Yi’ang laughed heartily but remained composed, calmly asking: “So did you commit the murders alone, or were they directed by Zhou Rong or Lang Bowen?”

“Of course I did it alone—those two don’t know anything about it. Zhou Rong and Ye Jian were like brothers. Even if he knew Ye Jian was investigating him, he wouldn’t make a move against Ye Jian. I couldn’t let my brother know about killing to silence people. He’s taken care of me since childhood—he would definitely oppose me doing this. I could only solve these troubles for him myself.”

“Don’t take all the blame yourself. I don’t believe you dared to do this without Lang Bowen’s authorization.”

“It was just me.”

“I’ll have to interrogate him to know. Where is he?”

“He’s at…”

“Where is he?”

“I don’t know where he is.”

Several police officers laughed. Just now, Lang Botu’s momentary expression clearly showed he knew where Lang Bowen was. Since it was confirmed he knew Lang Bowen’s whereabouts, interrogating it out of him was just a matter of time.

Zhang Yi’ang exhaled easily and shook his head: “I said all that to you just now, waiting for this one sentence from you. You think I really didn’t know Ye Jian’s hints? Don’t be ridiculous!”

He smiled contemptuously. The police officers in the monitoring room all looked at him curiously.

“When Ye Jian had his incident, I quickly realized Ye Jian was the accuser. But as an outsider investigating Zhou Rong, what was my biggest worry? Worrying whether there were Zhou Rong’s people in the police bureau. Because this matter involved Lu Zheng’s murder and connections to certain leaders behind it at the Provincial Public Security Department, I couldn’t be one hundred percent confident even in those closest to me. Ah, the bitterness in my heart then—no one knew.” He looked toward the monitor with a complex expression. Although the people in the monitoring room knew he couldn’t see them, everyone nodded vigorously, indicating they understood Director Zhang’s inner feelings. Li Qian even said silently, “Actually I understand you,” her eyes reddening.

“At that time I had to investigate secretly while not letting people know what I’d discovered. I could only play the fool—sometimes I had no choice but to go along with mistakes. But in my heart I was very clear about how the investigation should proceed. For us to get through one case after another to today—it hasn’t been easy!”

All the criminal police empathized and sighed—indeed not easy.

“Fortunately we investigated cases together, fought together. After being tested through so many battles, I’m gratefully discover that every one of our brothers is upright, all excellent criminal police!”

The hands of all these police officers in the monitoring room involuntarily clasped tightly together—these words were so heartwarming!

“I temporarily made up a different version of the crime story for you just to provoke you, to force you to tell the truth! I was originally worried you wouldn’t fall for it. Who knew you’d take the bait so easily? This battle of wits ended so quickly—it’s really boring.”

“You… what you just said was all made up?” Lang Botu swallowed the fresh blood, but his chest felt even more stifled.

“Otherwise, only a fool would believe such a stupid story, yet you believed it.”

The criminal police in the monitoring room finally breathed a sigh of relief. So what Director Zhang said earlier was all made up—such a story “only a fool would believe,” yet they almost believed it along with him. They all mocked themselves for also being fools for once. Director Zhang’s interrogation techniques were truly profound and inscrutable—with these words he blasted out Lang Bowen’s whereabouts and even made Lang Botu cough up blood. Truly brilliant.

“You…” Lang Botu endured his internal injury. “How exactly did you come to suspect me?”

“About that…” Zhang Yi’ang smiled mysteriously and pointed at his head. “Intuition—a criminal police officer’s intuition!”

Everyone froze in place. After several seconds, Zhang Yi’ang stood up and pushed open the door. He didn’t even need his crutches anymore. With his hands behind his back, he departed leisurely, leaving everyone only a silhouette that seemed to have two characters written across it out of thin air—Master Detective.