The forensic experts performed autopsies on the deceased Lü Yuchan, Ning Yaohong, and Li Zihan, and conducted toxicological tests on their stomach contents. They discovered that all of the food contained the highly toxic substance cyanide. Furthermore, cyanide was also detected in the cola bottle and vomit samples taken from the scene and brought back to the forensic laboratory.
However, no cyanide was detected in the leftover food taken from the refrigerator at the scene or in the bowls from the stove.
The situation was very clear: the victims died of cyanide poisoning after drinking cola laced with the chemical.
Upon learning of this result, Wu Shuqi, Sun Rumin, and the other officers involved in the case were not very surprised. They had suspected cyanide poisoning during the initial scene investigation, but due to the gas explosion, they leaned more towards carbon monoxide poisoning as the cause of death. They realized that this case was significant and complex and that an investigation should be launched as soon as possible.
However, the investigators were puzzled. Cyanide is a strictly controlled chemical, and it is difficult for ordinary people to access it. Who poisoned them, and how did they obtain it? What deep-seated hatred existed between the poisoner and the victims? Where and under what circumstances did the poisoner administer the poison?
The police felt that Ning Yaohong, as a woman with mental illness, was unlikely to have access to cyanide. Even if she managed to obtain it, she would have to go through security checks at the train station or airport, and carrying dangerous chemicals would be detected and confiscated by security personnel.
As for Lü Yuchan, they couldn’t think of any reason why she, a normal person, would poison herself along with others, so her suspicion was temporarily ruled out.
Li Yuehua was a strong suspect, but it was difficult to justify from a rational standpoint, since the deceased were all his relatives and friends.
Could it be that the poisoner intended to harm Li Yuehua, but three innocent people became accidental victims?
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Were the two colors of corpses for both cyanide poisoning and carbon monoxide poisoning very similar, prior to the victims of Lü Yuchan and Ning Yaohong passing, in order to create the reality that the victims passed away due to carbon monoxide poisoning, was the gas cylinder and gas stove turned on in the room?
If this hypothesis holds, then there is no doubt that the murderer has common knowledge of the above two color corpses, that he used this very well to create the illusion that the victim died of carbon monoxide poisoning, the purpose is to try to interfere with police detection line, to escape legal sanctions.
However, if the murderer has carefully created the reality of the situation, then why does he not destroy or take away the cola bottle with obvious traces of the crime at the scene? Subjectively speaking, wouldn’t it be more confusing for the police to determine the cause of passing if they had disposed of the cola bottle? Could it be that the murderer forgot to deal with it at the time because of panic and fear?
One question after another, like a rolling dark cloud swept away by the hurricane, was churning in the hearts of the police.
Before the post-mortem results of Lü Yuchan, Ning Yaohong and Li Zihan were sent out, the leaders of the Golden Sea Tang Private Security Bureau took it lightly and organized criminal investigation, technical investigation, visual investigation, and cyber investigation to hold a case analysis and judgment meeting, and established a special investigation team. The Party Committee of the bureau appointed Wu Shuqi as the leader of the investigation team and Sun Rumin as the deputy leader of the investigation team.
The special investigation team is divided into three groups: criminal technology, information analysis and judgment, and investigation and pursuit.
Wu Shuqi believed that the most important task was to conduct a comprehensive investigation of the suspects and a new investigation and judgment of the scene of the crime, to obtain surveillance from major areas to find clues, and to visit and find witnesses in order to find the perpetrator.
In order to complete this task as soon as possible, Wu Shuqi divided the action team into three groups to carry out work simultaneously according to the division of responsibilities: one group was led by her, along with visual investigation and technical investigation personnel, to the scene of the crime to collect evidence; one group was led by Wu Zhi, along with criminal investigation personnel, to bring Li Yuehua back to the Criminal Investigation Bureau for interrogation; and one group was led by Sun Rumin, along with criminal investigation personnel, to find Xiong Zhiyang, whose suspicion was no less than that of Li Yuehua.
Yesterday the police had notified the deceased’s family members to go to the post-mortem examination site today, so that the deceased’s family members could understand the post-mortem examination situation, which was conducive to letting the family members assist the police in finding out the truth of the case. However, what was surprising was that neither Li Yuehua nor Xiong Zhiyang went to the scene.
That cola bottle that tested positive for cyanide is an important piece of evidence in this case. To solve the case, the police must find out the source of the beverage and who poisoned it.
Wu Zhi and his colleagues controlled the haggard and unkempt Li Yuehua outside a hotel.
When Li Yuehua learned that his wife, son, and others had died of cyanide poisoning, he looked very surprised. He admitted that he had bought a bottle of cola at a convenience store outside his community on the evening of July 14, four days before the incident. He denied poisoning the cola. He said with tears in his eyes that the deceased were his wife, son, and friends, how could he possibly poison them?
He emphasized that he did not know that his wife and son would go to Jincheng this time. It was only when his wife called him when they arrived at his doorstep that he found out, trying to prove his innocence.
He also recounted the process of buying the drink and later drinking and placing it: he watched the news broadcast at home for a while and then went out to buy cigarettes. He felt thirsty and bought a liter bottle of cola. Then he took it back. After returning home, he unscrewed the bottle cap and poured two glasses to drink. He put the rest in the crisper layer of the refrigerator and never touched it again, because he forgot about it.
When the local police investigated the scene of the incident, they did not find the cola in the refrigerator, so it was determined that the bottle of cola that Li Yuehua put in the refrigerator was the bottle of cola that Ning Yaohong, Lü Yuchan, and others had drunk with cyanide in it.
Wu Zhi reported the situation provided by Li Yuehua to Wu Shuqi. Wu Shuqi and her colleagues went to the convenience store that Li Yuehua mentioned. By retrieving the surrounding surveillance footage, they saw Li Yuehua entering the convenience store to buy cigarettes and cola at 7:12 p.m. on July 14, confirming that what he said was true.
Li Yuehua said that he did not know in advance that his wife would take his son to Jincheng to find him. However, when the police investigated the scene, the children’s toy car that was considered to have caused the gas explosion puzzled Wu Zhi. Since he did not know that his wife and son were going to come, why did he buy the toy car and put it at home? Was he deliberately concealing something from the police?
So, Wu Zhi asked him when the children’s car was bought, where it was bought, and who it was bought for. Li Yuehua said that it was bought online last year for his son to play with. At that time, his son lived in that house.
Seeing that Li Yuehua seemed to be thinking incoherently, Wu Zhi thought that what he said might be false. However, in order to consolidate the evidence chain, Wu Zhi thought it was necessary to check his online purchase record of the toy car.
Speaking of the fire accident caused by the toy car charging at home, Li Yuehua was heartbroken and said that he would hold the unscrupulous merchant legally responsible.
Wu Zhi assumed that the murderer was not Li Yuehua but someone else. Then the murderer must have committed the crime at some point before Li Yuehua bought the drink. The situation should be like this: the murderer either sneaked into the house while Li Yuehua was not at home, or followed Li Yuehua into his house under some pretext, or made Li Yuehua close the door outside the house to let him enter the house, and then found an opportunity to poison him.
So, Wu Zhi asked Li Yuehua when he had gone out from the time he bought the drink until before the incident, how many times he had gone out, when he had returned home, whether he had seen anyone go to his house, and whether he had forgotten to close the door when he went out.
Li Yuehua answered one by one. He had gone out a total of six times in the past few days. As for the specific time of going out and returning home, he only gave a general range, because he didn’t deliberately remember it. He claimed that no one had been to his house in the past few days. He was sure that he had closed the door properly every time he went out.
However, he provided Wu Zhi with an important piece of information: on July 18, after he learned that his wife had arrived at his doorstep, because the door was locked, and because he was away from home for business development needs, he did not intend to go home that day, so he asked his wife to find a locksmith to unlock the door. He remembered that the time he talked to his wife was around 11:30 a.m. At that time, he had just finished refueling and drove out of the gas station.
Wu Zhi looked at his phone and checked his call record with Lü Yuchan: 10:43, the call time was 37 seconds, proving that he had not lied.
Li Yuehua continued to say that forty minutes after that call, his wife called him and said that the lock had been changed. She saw a locksmith’s advertisement posted on the wall of the corridor and called the locksmith. The locksmith arrived at his doorstep more than ten minutes later.
Wu Zhi reported these important situations to Wu Shuqi.
Wu Shuqi immediately sent someone to investigate the locksmith’s phone number and find him to understand the situation. She felt that this was an important clue. In addition, she retrieved the elevator surveillance footage of the apartment building on July 18 at noon and found that at 11:13, a middle-aged man in a cyan uniform carrying a tool bag appeared in the video. Through identification, it was determined that he was the locksmith.
He took the elevator from the first floor to the seventh floor and exited the elevator. The time he re-entered the elevator from the seventh floor was 11:35. He took it to the first floor and exited the elevator.
Unlocking, it involves the personal safety and property safety of citizens. Regular locksmith companies are registered with the Public Security Bureau. Although the locksmith’s clothes were very formal, his identity still needs to be verified.
Wu Zhi had suspected that Li Yuehua and Lü Yuchan had an extramarital affair. After repeated and stern questioning by him, Li Yuehua finally admitted that he and Lü Yuchan did indeed have an improper relationship.
Wu Zhi then asked Li Yuehua whether Xiong Zhiyang knew that you and Lü Yuchan had an extramarital affair. Li Yuehua said that he knew, and that Xiong Zhiyang had repeatedly divorced Lü Yuchan because of this.
As for why Lü Yuchan appeared at Li Yuehua’s home on the day of the incident, Li Yuehua explained that after he learned that his wife had taken his son to his doorstep, he called Lü Yuchan and told her about this. Lü Yuchan said that she would come and meet my wife. He persuaded her not to come. He was worried that his wife would suspect that his relationship with Lü Yuchan was unusual, which would cause conflict. She said, don’t worry, I have my own strategy and will not let her know about your false relationship.
Sun Rumin’s group also took the suspect Xiong Zhiyang from his decoration company to the Criminal Investigation Bureau.
As soon as Xiong Zhiyang was brought back to the Criminal Investigation Bureau, Sun Rumin asked Wu Zhi about the interrogation of Li Yuehua. He believed that knowing the interrogation situation would help him gain a spiritual advantage when interrogating Xiong Zhiyang. Wu Zhi generally told him the situation.
The police used technical investigation methods to retrieve the WeChat chat records between Xiong Zhiyang and Lü Yuchan, and found that Xiong Zhiyang’s messages contained threatening words such as “You and Li Yuehua go to hell,” “I will make you look good,” and “You deserve it.”
Xiong Zhiyang’s suspicion of committing the crime suddenly increased.
“Since ancient times, adultery has led to murder!” Sun Rumin muttered these words in his heart.
Sun Rumin thought, if Xiong Zhiyang is indeed the murderer, then he must have committed the crime while Li Yuehua was not at home and opened the door of his house. How did he enter the house? If the door lock was broken, then Li Yuehua would definitely notice something and call the police when he went back. However, our investigators did not hear him say that his door lock had been pried open, nor did we hear the comrades from the Area police station say that he had reported the case. Could it be that Xiong Zhiyang had the key to his house? Well, it must be so! I guess out of trust, Li Yuehua gave the key to his house to Lü Yuchan, and Xiong Zhiyang knew about this, so he found an opportunity to take the key and make a copy, and then returned the original key without anyone knowing.