Qin Jinjun read the information carefully, took out a blank A4 piece of paper from the printer on Lan Jingguo's desk, and took a black signature pen from the pen holder next to the computer screen, and excerpted the information she thought was important in the information:

The first suspect: Guan Qin, Chinese New Year's Eve, single father, a former paper mill worker, changed careers to become a courier a few years ago when the logistics industry took off. His daughter's name is Guan Xiaolin, a victim of fraud half a year ago, committed suicide on the night of September 6, 2013, reported to Guan Qin, on the morning of the 7th, he found Guan Xiaolin's body lying in a pool of blood in the kitchen, she had a deep and long wound on her neck, and she was holding a kitchen knife in her right hand. After the police arrived at the scene, they made a brief record of Guan Qin, who had an emotional breakdown, and Guan Qin said that Guan Xiaolin had been haunted by the fact that she had been wrongfully stolen her wallet half a year ago, and suffered from moderate depression as a result. The tragedy occurred on the night the fraud was reported, and according to the police, Guan Xiaolin should have gone to the kitchen to cut her throat with a kitchen knife after Guan Qin fell asleep.

The second suspect: Ouyang Yan, 47 years old this year, serves as the deputy chief attending physician of pediatric surgery in the Third Hospital of Zhongguang City, has been married twice, and has a son with his second wife, Ouyang Bin. Ouyang Bin was a victim of a fraud three months ago, after which he suffered from a mental illness called kleptomania, often stealing stationery, textbooks, homework books and other items from classmates in class, and then throwing the stolen things into a trash can somewhere on campus. He was expelled from school by the principal two months ago, and since then Ouyang has been able to study at home.

The third suspect: Tong Xin, Chinese New Year's Eve, working as a general attending physician in gynecology at the Third Hospital of Zhongguang City, husband Ouyang Yan, and son Ouyang Bin.

The fourth suspect: Wang Gaoyuan, now Chinese New Year's Eve six, a bus driver, is the father of Wang Ruoxuan, a recent victim of fraud.

Qin Jinjun took out a red signature pen from the pen holder and drew an asterisk in front of the name of the first suspect.

Putting down the pen, Qin Jinjun manipulated the mouse to close the folder, and opened the file next door named the suspect's interrogation video, which contained four video files. Since the second murder occurred yesterday, the police immediately investigated the two cases together, thus locking the guardian of the victim of the fraud case as the suspect, until now it is very difficult to record the suspect's confession and verify all the alibi provided by them, Qin Jinjun nodded affirmatively, and then clicked on the interrogation video.

The video progress bar begins to move slowly, and the screen shows a scene inside the interrogation room, with an Arabic numeral printed in black paint visible on the door of the interrogation room that is opened: 5. A policewoman walked into the No. 5 interrogation room with a man wearing overalls printed with the logo of a famous logistics company. Closing the door of the interrogation room, they walked to the table and sat down face to face, Detective Tang took out her notepad and pen and prepared to take notes, the lower right corner of the screen shows the time of recording the video: 2013.9.13. 19:24:49.

"Thank you, Mr. Kwan, for taking the time out of your busy schedule to come." Criminal Police Tang made a polite opening remark.

Guan Qin replied impatiently: "Hurry up and ask whatever you want, don't delay my time." ”

"Yes, Mr. Kwan. Where are you today from 12 noon to 1 pm? Criminal Police Officer Tang asked straight to the point.

"When it was almost twelve o'clock, I just finished delivering an express mail, so I went to a random store near there for lunch, and continued to deliver the express after eating." Guan Qin replied.

"Do you have a reserved receipt?" Detective Tang asked.

"The receipt was placed on the table and not taken away." Guan Qin replied.

"Where is the address of the shipment delivered before lunch?" Detective Tang asked.

"Miss Police, don't tease me, I have to send so many express mail in a day, how can I remember the address of each express mail." Guan Qin said sarcastically.

"The address does not need to be specific to the house number, the police only need to know the approximate location, which district in Zhongguang City, and which street do you remember?" Detective Tang asked.

Guan Qin's face softened, and he replied: "Ping'an Street, Zhongnan District." ”

"What time is lunch?" Detective Tang asked.

“12:16。” Guan Qin replied.

"Why do you know so accurately?" Detective Tang asked.

"Because I habitually look at my watch every time I finish eating, which is a habit I developed after working as a courier." Guan Qin replied.

"What is the address of the first shipment after lunch?" Detective Tang asked.

"It's also from Ping'an Street, and I've been in charge of the express delivery of that area since Monday." Guan Qin replied.

"Okay, I don't have any more questions to ask, thank you again for your cooperation." Detective Tang covered his notebook.

"Can you ask what's going on? What does that mean woman have to do with me? My daughter just died a few days ago, so I'm also a victim, and you police don't investigate the case well, and you still suspect what is going on with us victims! Guan Qin couldn't help but erupt.

"Please calm down, this is just a regular questioning, and the police are not deliberately targeting anyone." Criminal Police Officer Tang said in a calm tone.

"Then why didn't the police do more investigation when my daughter died? After simply making a transcript and wrapping my daughter's body in a white cloth, my daughter's death will not be a problem, right? Guan Qin got up and slapped the table, very emotional.

"Your daughter committed suicide." Detective Tang's tone was still calm.

"Hahahahahaha, she was forced to die! You should look into it! She was driven to death by the brutes who wronged her for stealing! She was driven to death by me! Guan Qin let out a maniacal laugh, he roared loudly in the interrogation room, and then began to cry, and continued to shout: "I forced her to death!" I shouldn't have scolded her for being a thief! Daughter, I'm sorry! It's Dad who wronged you! Come home! Come back to me! Those brutes deserve to die! The heavens have eyes! Let them all go down to Hades. ”

Guan Qin cried and screamed while lifting a chair and smashing it on the table, the scene fell into chaos for a while, and Criminal Police Tang dialed the phone and asked the police officers outside to come in to support. Soon, three or four tall police officers rushed into Interrogation Room 5 and subdued the guards on the ground in three or two times. After the officers took Guan Qin out, Detective Tang patted his chest and walked to the miniature camera to turn it off.

This is the end of the video, Qin Jinjun picked up the red pen on the table and added her own thoughts next to the excerpts of the first suspect, Guan Qin, but her notes were written in a mess, and they were sorted out as follows:

Guan Qin is the most suspicious, and there are three reasons for this: first, he is engaged in two professions; the second is the location of his delivery on the day of the crime; The third is his motives.

Guan Qin has worked in a paper mill for a long time and has a certain understanding of chemical raw materials, one of which is industrial cyanide*. In other words, he was very knowledgeable about the extraction of cyanide and its properties, thus increasing his suspicion in the first murder. And his current profession is a courier, in this era, the nature of the courier's profession is universal, their figure is all over the community, all residential buildings, as long as the residents have a computer at home, there will be couriers in the neighborhood from time to time, even the second murder of such an old residential building is no exception. It is normal for couriers to appear frequently in residential buildings, and the residents and the deceased, Ms. Zhu, naturally do not be too wary of him. Even if the deceased had met Guan Qin before, as long as he wore a mask or something to cover his face, he might not be able to recognize him. In this way, the identity of the customs courier is in line with Qin Jinjun's inference about the second murder.

After the police investigation of the courier company where Guan Qin worked, the company's courier manager (Guan Qin's immediate boss) claimed that Guan Qin applied to him on September 7 to be transferred to the express delivery work in the Ping'an Street area, and he quickly approved it, and Guan Qin had been delivering mail near Ping'an Street since September 8, and the residential building where the second murder occurred was in Ping'an Street.

As for Guan Qin's motives, it couldn't be more obvious, his daughter chose to commit suicide because she couldn't stand the huge stimulation brought by the truth of the fraud case, and he hated all the members of the fraud gang to the core. This, coupled with his insane behavior in the police interrogation room, further proves that his daughter's death has distorted his spirit.

Although Guan Qin is very consistent with the characteristics of the murderer of the two murders, he was having lunch at the time of the second murder, and the police visited the store that Guan Qin said this morning, and there was indeed a record of his consumption at noon on the 13th, so the alibi he provided was established.

The case has a big doubt due to the appearance of Guan Qin, why did he apply to be transferred to Ping'an Street to deliver express mail?

Qin Jinjun wrote down the question on a piece of paper and repeatedly drew horizontal lines under the question with a red pen.

"Don't break the paper." Lan Jingguo's voice suddenly sounded behind him.

Qin Jinjun shook his body in fright, threw the pen on the table, turned his head and scolded Lan Jingguo.

"The analysis is very detailed, but why do you only analyze this suspect named Guan Qin, and how many others?" Lan Jingguo walked over to Qin Jinjun and sat down and asked.

"There's no need. Although the other three suspects had a motive for committing the crime, they did not commit the homicide. Let's talk about Ouyang and his wife first, their only seedling Ouyang Bin suffered from mental illness after the fraud case, which had a great impact on the couple, but not long ago Ouyang Yan was promoted to deputy director, and his wife Tong Xin was pregnant with a second child, which can be described as double happiness, and the couple will definitely not destroy their future in this period of life at the peak of their lives. Wang Gaoyuan is even more impossible, his son Wang Ruoxuan did not suffer substantial losses because of me, and received a small amount of compensation from the supermarket. And his wife believes in Buddhism, so there is no big suspicion. Qin Jinjun shrugged, picked up the milk tea on the side and took a sip.

"Eliminate the other three suspects, you think Guan Qin is the most suspicious, but I don't think he is the murderer." Lan Jingguo touched the stubble on his chin.

"I didn't say he was a murderer. With his current state of mind, it was impossible for him to come up with such a well-thought-out murder plan. The corner of Qin Jinjun's right mouth rose slightly, revealing a smug smile, and continued: "But there are many doubts about him, which are inextricably linked to the case itself, and it is difficult for me to exclude him from the case." My gut told me that he and his daughter were the key to this serial murder case, and that I could find the real killer through them. ”

"Well, then I'll immediately send someone to bring Guan Qin over for interrogation again." Lan Jingguo was about to pick up the landline microphone and pick it up for Xiao Fan.

Qin Jinjun stopped him and said, "You don't need to bring Guan Qin to the police station, I want to give him a home visit." ”