Chapter 20 Crime Scene Investigation

Wu Jun sighed deeply, stood up tall, strode to the door to shut and lock it in one fluid motion.

Upon returning, without heeding Jiang Yuan's expression, Wu Jun pulled out a small box from the drawer, opened it, and revealed a red Guan Yu pendant that was but an inch long and half an inch wide.

The pendant had two red cord strings at the top, meant for hanging around the neck, but Wu Jun simply stretched and hung it on the back of the office door.

"Come and pay your respects," Wu Jun said, "and remember to watch your words in the future."

"This..." Jiang Yuan hesitated before asking, "Is it appropriate to worship Guan Yu inside the station?"

（Guan Yu: a deity worshipped in Chinese folk religion, popular Confucianism, Taoism, and Chinese Buddhism. Gangsters often worship Guan Yu to pray for blessings.）

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

"Where... did it come from?"

"Eight years ago, the Hong Kong Police Force came to Shan Nan Province for a police exchange, and an officer sold... well, more like half-sold, half-gave it to me," explained Wu Jun as he clasped his hands together and bowed to Guan Yu, continuing, "You know, our entire national police system is actually learning from Hong Kong. The Shenzhen Police Force learns the best, having the most exchanges and the money too, so they replicate it quite well. And frankly, over the years, there's been a lot we could learn from the Hong Kong Police Force."

"Watching TV dramas, it seems like forensic doctors in Hong Kong are also very impressive," said Jiang Yuan as he walked over.

Wu Jun curled his lip: "I wouldn't know about that; they didn't send any forensic doctors last time."

"So, did you learn the technique of worshiping Guan Gong through the exchange?" inquired Jiang Yuan, noting that the Guan Gong pendant was made of agate and thinking to himself that it seemed rather unpretentious.

Ignoring Jiang Yuan's comment, Wu Jun directed, "First spit three times, then bow; fewer cases means less work for us and a more harmonious society, right?"

Jiang Yuan spat three times and obediently followed with his hands clasped together, bowing deeply.

At his home, there were plenty of decorations like Guan Gong, Bodhisattvas, Maitreya Buddha, the Three Pure Ones, and crosses made from various materials such as jadeite, Hetian jade, or different kinds of gemstones, without much attention to particularities.

After watching Jiang Yuan finish worshipping, Wu Jun checked the time, let out a sigh of relief, stored the pendant back in the box, tucked it into the drawer, reopened the office door, and then said to Jiang Yuan, "In acquiring knowledge, we can't confine ourselves to what's written in books, right?"

Jiang Yuan agreed, "Right, right, right."

Looking at his phone with satisfaction, Wu Jun remarked, "See, no phone calls have come through. What does this tell us? It shows that our worship just now was effective."

Jiang Yuan nodded in agreement and quietly started reading the novel "Great Doctor Ling Ran."

That evening, a call from Captain Huang Qiangmin came to Jiang Yuan, informing him of progress in the gang theft case—the suspect imprisoned had confessed to multiple accomplices.

For the next two days, all the updated news revolved around the gang theft case.

The suspect brought back by the criminal police force got his fingerprints taken again, which were then compared with the prints left at the crime scene, increasing the number of confirmed cases.

In criminal cases, the saying "every thief has a careless moment" is quite common.

Modern people are aware that fingerprints can trace back to them, and that any place might have surveillance cameras, but when it comes time to commit the crime, those who are constantly mindful to conceal themselves remain a minority of a minority.

Wearing gloves while committing crimes is easy, but before and after wearing gloves, one cannot guarantee not touching objects at the scene. Some suspects, after finishing their deeds, remember leaving something behind, or accidentally touch doorknobs or similar items...

Being absent-minded and making careless mistakes are common to everyone, not only in ordinary work and life but also throughout the criminal process and the lifespan of a criminal's career.

Plus, with multiple testimonies and physical evidence like modified vehicles, it's very difficult for several individuals to escape some part of the responsibility.

During this phase, Jiang Yuan's role was merely to assist in the recheck and comparison of the work.

Previously hard-to-match fingerprints now had real people to compare with, which made the process much easier. The younger members of the gang had also left a deep imprint within the official system. Next time they committed a crime, there would be no worries about mismatches!

A week went by, and just as Jiang Yuan began pondering how to spend the weekend, Wu Jun's phone started rhythmically vibrating.

Wu Jun glanced at it, his expression changed, and he promptly answered, saying, "Captain Huang."

After a few words, Wu Jun ended the call and with a clear voice announced, "There's been a murder. Prepare in three minutes; take my investigation kit and we'll take the Crime Scene Unit's Iveco to the crime scene."

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

Wu Jun also showed a grave expression. After getting his gear ready, he touched the Guan Gong box in the drawer, sighed, and said to Jiang Yuan, "You see, praying can hold things off for at least a week, but in the end, we can't escape it."

...

Wu Jun and Jiang Yuan traveled in the Crime Scene Unit's Iveco, adapted for fieldwork, as quickly as possible to the scene.

The Crime Scene Unit's vehicle is essential at the county bureau level, something that had to be acquired no matter how strapped for funds. Wealthy bureaus could afford professional and large vehicles, while less affluent ones could make do with modifications.

Inside the vehicle, various equipment was ready, including an assortment of investigation kits, evidence bags, a variety of tapes, powder, tags, and more. It also provided space for storing corpses, saving the technicians a lot of preparation time.

Jiang Yuan was slightly nervous and exhilarated.

He had completed a full five-year forensic studies course at the medical university. Attending lectures, reviewing, working on projects, writing papers—he had gone through the whole process, but he had only seen one corpse at a crime scene. Going to a scene again, it would be false to say he was not excited.

Arriving at a small red brick building in the suburbs, the police officers who had arrived earlier had already established control. Several police cars were parked haphazardly below, and some officers were dispersed, speaking with people lounging around or walking in the yard.

Jiang Yuan flashed his credentials and, carrying a case, quickly ascended to the third floor with Wu Jun.

The room where the incident occurred was less than ten meters from the staircase, and the area was chaotically surrounded by residents of the building who were rubbernecking.

Jiang Yuan, who had just obtained Level 4 Crime Scene Investigation credentials two days prior, involuntarily furrowed his brows at this scene.

Since he was still a newbie, Jiang Yuan didn't have the authority to say anything. He flashed his credentials again and entered the room with his head down.

Housing from thirty or forty years ago was generally smaller in size, about forty square meters, with the living room getting indirect light. A larger bedroom had ample lighting, but it was cramped with several police officers and a body lying across the room.

Fortunately, the smell of the fresh corpse was still bearable, making the room's environment somewhat tolerable.

"Suit up first." Wu Jun's expression was serious as he signaled Jiang Yuan to open the investigation case.

Jiang Yuan donned a face mask, gloves, cap, and goggles, then stood beside Wu Jun, taking the opportunity to observe the corpse.

The deceased was wearing only a pair of briefs, half-naked on the bed with a knife in his chest, bleeding profusely. Looking down, Jiang Yuan saw that the blood had almost soaked the dirty carpet in the bedroom, while an evidence technician was painstakingly taking photographs from above down.

Criminal scene photography is a specialty in itself, especially before the popularity of digital cameras. Officers armed with professional cameras had to use as few rolls of film as possible to convey rich information, which took years of practice to master.

Specifically during photography, complete criminal scene photography includes photos of the scene orientation, overall, center, and details, as well as technical methods like opposite shooting, cross shooting, and segmented shooting.

However, after film rolls fell out of favor, the role of crime scene photography in small localities was quickly superseded by evidence technicians. If needed, detectives, forensic doctors, and even traffic police could all take on the task.

Of course, basic standards still had to be maintained, especially for major and serious cases, where officers strived to follow protocol as much as possible. For example, photographing a corpse had to be done vertically, not at an angle or indiscriminately like an ordinary person taking a photo.

After the photography was finished, Jiang Yuan proceeded with the external examination of the body with his mentor Wu Jun.

Being a forensic doctor requires the accumulation of extensive experience. Even after five years of medical school, Jiang Yuan still had to learn gradually from Wu Jun.

Wu Jun also took several photos, particularly of the items around the body, before turning to Jiang Yuan and asking, "Do you recognize this body?"

"I…" Jiang Yuan nearly ran out of breath, glanced helplessly, and said, "How could I possibly know everyone."

"You're a native of Ningtai County, you could run into an old classmate or friend." After Jiang Yuan took a careful look, Wu Jun sighed regrettably and said, "If you really don't recognize him, we'll have to start from scratch. I'll have you take notes."

"One male corpse, 170 centimeters in length... pale skin… black hair, intact scalp…" Wu Jun spoke while also checking Jiang Yuan's notes, nodding again and again.

Jiang Yuan's records were quite standardized, even more detailed, such as noting the orientation and posture of the body at the beginning, and adding "no jaundice" after mentioning pale skin…

From Wu Jun's perspective, Jiang Yuan, able to do this much, seemed more like a colleague than an apprentice.

Jiang Yuan himself felt increasingly committed as he wrote.

The range and depth of the newly acquired skill "Crime Scene Investigation (LV4)" was much greater than he imagined. It included not only the typical scene investigation but also the forensic investigation and trace examination, among others.

Within forensic investigation, surface examination of the body was also included.

As a result, the skill "Crime Scene Investigation (LV4)" was proving to be hugely significant.

Jiang Yuan suppressed his inner thoughts and earnestly completed the external examination with Wu Jun. Next, they began to collect and examine DNA evidence.

DNA evidence refers to potential sources of DNA on physical evidence, commonly including bloodstains, seminal stains, saliva stains, or isolated droplets of blood, and so on.

Jiang Yuan started around the body, collecting hair and skin flakes. Although there was a high probability that they belonged to the victim, only testing would confirm it.

Trace evidence around the body was usually considered more reliable, thus warranting extra careful examination. Wu Jun was getting older; though not yet suffering from poor eyesight, his sensitivity to scrutinizing small evidence was somewhat diminished.

On the contrary, Jiang Yuan had a keen eye and quickly collected various pieces of evidence, several of which Wu Jun had not even clearly seen.

Seeing this, Wu Jun took the opportunity to straighten up and relax a bit. Bending over to examine evidence at a half-raised bed was particularly uncomfortable for someone his age.

Jiang Yuan, a recent graduate, was at his physical peak, full of energy. He had also just acquired a new skill, so he didn't feel tired at all. After thoroughly collecting evidence around the body, he started gathering blood evidence.

He first chose a clot of blood near the deceased's thigh, dipped a cotton swab in the blood but didn't place it directly into the evidence bag. Instead, he took out a piece of filter paper, wrapped the cotton swab in it, and folded it into a triangle.

Just this one action caught the attention of the evidence technicians and Wu Jun nearby.

Others quickly understood why he did this. A blood-soaked cotton swab placed directly into an evidence bag risks contamination and seepage of blood out of the bag, causing secondary contamination—biological materials can't be stored in plastic evidence bags to prevent decay. Furthermore, the blood-dried cotton swab becomes difficult to examine and reuse with time.

However, wrapping it in filter paper changes the situation. The blood seeping out of the cotton swab is readily absorbed by the filter paper, and there's no worry about further leakage thanks to the paper's absorption capacity. In the lab, cutting just a piece of the filter paper is sufficient for DNA testing, and the rest remains well-preserved.

Understanding is one thing, but for crime scene technicians accustomed to tossing multiple cigarette butts into one evidence bag, no one had informed them this method was an option.

"Where did you find this apprentice?" the crime scene technician asked Wu Jun in astonishment.

Wu Jun remained calm and shook his hips slightly, slowly saying, "Some operations, I just haven't bothered to do myself."