Chapter 20 Crime Scene Investigation

Wu Jun sighed, stood up, walked to the door, closed the door and locked it in one go.

When he came back, Wu Jun ignored Jiang Yuan's expression and took out a small box from the drawer. When he opened it, it was a red Guan Yu pendant that was only one finger long and half a finger wide.

There were two red strings on the top of the pendant, which were used to hang around the neck, but Wu Jun stretched his body and hung it directly behind the office door.

"Come and worship." Wu Jun said, "Be careful with your words in the future."

"This..." Jiang Yuan hesitated for a moment and said, "Is it appropriate for us to worship Guan Yu in the bureau?"

Wu Jun said with a stern face, "Do you know where I got this Guan Yu?"

"Where...from?"

"Eight years ago, the Hong Kong police force went to Shannan Province for police exchanges, and a police officer sold...half sold and half given it to me." Wu Jun put his hands together and worshipped Guan Yu, saying, "You know, our national police system is actually learning from Hong Kong. The Shenzhen police force learns the best, which means they have the most exchanges, more money, and learn like Hong Kong. And, don't tell me, the Hong Kong police force has a lot to learn from us over the years."

"Watching TV dramas, Hong Kong's forensic doctors seem to be quite powerful." Jiang Yuan walked over.

Wu Jun pouted: "Then I don't know, they didn't have a forensic doctor last time."

"So, you learned the skills of worshipping Guan Gong through exchanges?" Jiang Yuan saw that the Guan Gong pendant was made of agate, and thought to himself, it was quite simple.

Wu Jun ignored him and directed, "Puh, puh, puh three times first, then bow once more. With fewer cases, we can relax and the society will be harmonious, right?"

Jiang Yuan said "Puh, puh", then followed obediently, put his hands together, and bowed.

He also had many ornaments such as Guan Gong, Bodhisattva, Maitreya Buddha, Sanqing, and crosses at home, either jadeite, Hetian jade, or gemstones, but he didn't pay much attention to them.

Wu Jun waited for him to finish bowing, looked at the sky, breathed a sigh of relief, put it in the box, put it in the drawer, reopened the office door, and said to Jiang Yuan, "To learn knowledge, we can't be confined to the knowledge in the books, right?"

Jiang Yuan: "Yes, yes, yes."

Wu Jun looked down at his phone and said with satisfaction, "Look, there is no call, what does it mean? It means that what we just bowed is effective."

Jiang Yuan nodded in agreement, and silently opened the novel "The Great Doctor Ling Ran" to read.

In the evening, Captain Huang Qiangmin called Jiang Yuan and told him that there was progress in the gang theft case. The suspects in prison confessed several accomplices.

In the next two days, the updated news was all about the gang theft case.

The suspects caught by the criminal police team were fingerprinted again, and then compared with the fingerprints left in the case, and more and more cases were confirmed.

The so-called "one mistake in a hundred precautions" is actually quite common in criminal cases.

Modern people know that fingerprints can be traced back to themselves, and there may be cameras wherever there are people, but when it comes to committing a crime, only a few of the few can always pay attention to hiding themselves.

It is easy to wear gloves during the crime, but it is not necessarily guaranteed that you will not touch the objects at the scene before and after wearing gloves. Some suspects, after completing the case, remembered that they had left something behind, or accidentally touched objects such as door handles...

Things such as forgetting things and making mistakes are common to ordinary people. Not only ordinary people may appear in ordinary work and life, but also in the criminal process and even in the criminal career of criminals.

Coupled with multiple confessions and physical evidence such as modified vehicles, it is difficult for several people to escape part of the responsibility.

At this stage, Jiang Yuan only cooperated with some rechecking and matching work.

The fingerprints that were difficult to match before are now easy to match with real people. The young people in the gang have left a deep imprint in the official system. In the future, they will not have to worry about not being able to match when committing crimes!

This went on for a week. When it was the weekend, Jiang Yuan had already started to think about how to spend the weekend, and Wu Jun's phone began to vibrate rhythmically.

Wu Jun only took a look and his face changed. He immediately picked up the phone and said, "Captain Huang."

After a few words, Wu Jun ended the call and said in a clear voice: "There is a murder case. Prepare in three minutes. Take my investigation box and take the trace inspection car to the crime scene."

"Yes." Jiang Yuan replied, his heart pounding.

Wu Jun also had a solemn expression. Only after he had sorted out his equipment did he touch the Guan Gong box in the drawer, sighed, and said to Jiang Yuan: "You see, worshiping can at least keep off for a week, but in the end, it can't be avoided."

...

Wu Jun and Jiang Yuan took the on-site investigation vehicle modified from Iveco by the Criminal Division Squadron and rushed to the scene as quickly as possible.

On-site investigation vehicles are essential equipment for county bureaus, and they must be bought no matter how poor. However, those who have money can buy professional and large vehicles, and county bureaus without money can also use them after modification.

Inside the car, there are all kinds of equipment that have been prepared, including various types of investigation boxes, various evidence bags, various small brands of tape powder, etc. At the same time, space is reserved for parking corpses, which can save technicians a lot of preparation time.

Jiang Yuan is a little nervous and excited.

He completed five years of forensic medicine at the Medical University. I went to classes, reviewed, worked on projects, and wrote papers. After going through the whole process, I only saw one body at the crime scene. If I say I'm not excited when I go there again, I'd be lying.

When they arrived at a small red brick building in the suburbs, the police officers who had arrived earlier had already set up control. Several police cars were parked casually downstairs. Several police officers dispersed and questioned people in the yard to watch the excitement and walk.

Jiang Yuan showed his ID, then carried the box and quickly climbed to the third floor with Wu Jun.

The room where the incident occurred was less than ten meters away from the stairs. The surrounding area was messy and there were residents in the building watching.

Jiang Yuan, who had just obtained the crime scene investigation LV4 two days ago, frowned unconsciously when he saw this scene.

Jiang Yuan, who was still a newcomer, had no right to speak. He showed his ID again and lowered his head to enter the room.

The area of ​​rooms thirty or forty years ago was generally small, about only 40 square meters. The living room was indirectly lit. A larger bedroom was bright, but it contained multiple police officers and a corpse lying horizontally, so the feeling of crampedness was inevitable.

Fortunately, the smell of the fresh corpse was acceptable, making the environment in the room acceptable.

"Put on first." Wu Jun had a serious expression and motioned Jiang Yuan to open the investigation box.

Jiang Yuan put on a mask, gloves, hat, goggles and other items, then stood beside Wu Jun and observed the body.

The deceased was only wearing a pair of briefs, lying naked on the bed, with a knife in the chest, bleeding a lot. Jiang Yuan looked down and saw that the blood almost soaked the dirty carpet in the bedroom. The on-site investigation next to him was standing on a stool, taking pictures from top to bottom with great effort.

Criminal scene photography is also a special category. Especially before digital cameras became popular, police officers with professional cameras needed to use as little film as possible to present extremely rich information, and they had to practice for several years before they could really get started.

When it comes to shooting, complete criminal scene photography requires on-site orientation photography, on-site full-view photography, on-site center photography, on-site detailed photography, and other details such as opposite shooting method, cross shooting method, segmented shooting method, etc.

However, after losing the cover of film, the position of criminal scene photography in small places was quickly covered by on-site investigation. If necessary, criminal police, forensic doctors, and traffic police can also do it.

Of course, basic requirements still need to be met, especially for serious and major cases, the police still try to follow the regulations as much as possible. For example, when photographing a corpse, it must be photographed vertically, and not from the side like ordinary people do.

After Jiang Yuan finished taking pictures, he followed his master Wu Jun to do a surface examination of the corpse.

Forensic medicine is a profession that requires rich experience accumulation. Even though he has studied at a medical university for five years, Jiang Yuan still has to learn from Wu Jun bit by bit.

Wu Jun also took a few photos, especially of the items around the corpse, and then turned to Jiang Yuan and said, "Do you recognize this corpse?"

"I..." Jiang Yuan almost couldn't breathe, and looked helplessly, saying, "How could I recognize them all?"

"You are a native of Ningtai County, maybe you can meet a classmate or friend." Wu Jun waited for Jiang Yuan to take a closer look, then sighed regretfully and said, "If you really don't recognize it, you can only start from the beginning. I say you should record it."

"A male corpse, 170 cm long... pale skin... black hair, intact scalp..." Wu Jun said while checking Jiang Yuan's records, nodding frequently.

Jiang Yuan's records were quite standardized, even more detailed, such as marking the position and posture of the corpse at the beginning, and adding "no yellowing" after the pale skin...

From Wu Jun's point of view, Jiang Yuan, who can do this, is more like a colleague than an apprentice.

Jiang Yuan himself also felt more and more as he wrote.

The scope and depth of the newly acquired skill "Crime Scene Investigation (LV4)" are far greater than he imagined. It includes both the usual on-site investigation, the on-site investigation of forensic doctors, and the on-site investigation of traces, etc.

In the on-site investigation of forensic doctors, the external examination of the corpse is also included.

In this way, the role of crime scene investigation (LV4) is quite large.

Jiang Yuan suppressed his inner thoughts and carefully completed the external examination of the corpse with Wu Jun. Then, the two began to check and extract DNA samples.

The so-called DNA samples are physical evidence that may contain DNA, such as blood stains, semen stains, saliva stains, or isolated droplets of blood.

Jiang Yuan first extracted hair and dandruff around the corpse. Although it is very likely that it is the victim's own, it can only be confirmed after inspection.

Trace evidence around the corpse is usually considered to be more reliable, so it needs to be checked very carefully. Wu Jun is old, although he is not to the extent of being blind, but his sensitivity to delicate small evidence is somewhat weakened.

Jiang Yuan, on the contrary, quickly collected a variety of physical evidence, and Wu Jun couldn't even see several of them clearly.

Seeing this, Wu Jun simply took the opportunity to straighten up and relax a little. Bending over the half-high bed to do an examination is the most uncomfortable thing for an old waist expert of his age.

Jiang Yuan is a young man who has just graduated. He is in good physical and energetic condition. He has just acquired skills and doesn't feel tired at all. After collecting the physical evidence around the body, he began to collect blood evidence.

He first selected a pool of blood on the thigh of the body, dipped a cotton swab in the blood, and did not throw it directly into the evidence bag, but took another piece of filter paper, wrapped the cotton swab, and then wrapped it into a triangle.

This action alone made the on-site investigator and Wu Jun next to him stare.

Others could easily understand his operation. The cotton swab with blood sucked directly into the evidence bag is easy to be contaminated and easy to ooze blood from the evidence bag, which will form secondary pollution. In order to avoid corruption, biological samples cannot be stored in plastic evidence bags. Secondly, the blood in the cotton swab is easy to dry after the evidence is stored for a long time, which is not conducive to verification and secondary use.

However, the situation is different when wrapped with filter paper. The blood oozing from the cotton swab is easily absorbed by the filter paper, and with the water absorption capacity of the filter paper, there is no need to worry about leakage. When it is used in the laboratory, just cut a little of the filter paper on it, which is enough for DNA testing, and the rest is still easy to store.

Understanding is understanding, but for the investigator who pours multiple cigarette butts into an evidence bag on a daily basis, no one really told him that he could operate this way.

"Where did you find this apprentice?" The investigator asked Wu Jun in surprise.

Wu Jun shook his waist calmly and said slowly: "There are some operations that I am just too lazy to do."