Diary of a Criminal Investigator-Chapter 386: The Identity of the Second Body

Chapter 386: Chapter 386: The Identity of the Second Body

Sun Jun cooperated with the imaging investigation team to investigate the surveillance on the ring road, focusing on checking vehicles from a month ago, particularly those entering the ring road from North Mountain and exiting at the landfill.

This workload is actually considerable. The cold storage in North Mountain is the largest cold chain transfer base in the northern part of Haizhou City.

Every day, hundreds to thousands of cold chain transport vehicles come in and out of this cold storage area.

According to Haizhou City’s traffic management requirements, cold chain transport vehicles are only allowed to use the ring expressway and cannot enter the inner ring.

This means all vehicles entering the North Mountain cold storage must pass through the entrance and exit of the North Mountain ring road.

Thankfully, there’s also the restriction of the landfill exit, and cold chain transport vehicles are usually on long hauls, connecting to highways through the ring road.

"Mark this vehicle."

Sun Jun personally took charge, ensuring that every vehicle traveling to the landfill via the ring road a month ago, on a weekly unit basis, was scrutinized.

In the crime scene investigation lab, Yang Sen was conducting DNA analysis on the second corpse.

"How is it going?" 𝘧𝓇𝑒𝑒𝑤ℯ𝑏𝓃𝘰𝑣ℯ𝘭.𝘤ℴ𝘮

"I just extracted two bone marrow samples, but both failed processing, now working on the third one."

The success rate of DNA analysis isn’t always 100%, mainly depending on the material’s viability.

Judging by the state of self-decomposition in the second corpse, successful identification shouldn’t be a major issue, but it will certainly take time.

"Keep trying, try several times, if it doesn’t work, we’ll have to look at mitochondrial DNA analysis."

Yang Sen listened and felt a bit challenged: "Mitochondrial DNA analysis... I’m afraid it won’t be easy."

There are generally three methods for DNA identification.

The most common one is the conventional chromosome identification method, which involves examining blood cells, hair follicles, and other materials.

This method fully measures the human double helix DNA and compares it with the target DNA through segment allocation.

The testing technology for this approach is highly developed, with ready-made test reagents that most crime scene technicians can use after training.

Another fairly common method is the Y chromosome DNA analysis, which is often used in cases involving Qiang Jian.

Less common is mitochondrial DNA analysis, which differs from Y chromosome DNA analysis in that the former is paternally inherited, while mitochondria are maternally inherited.

This analysis method is ideal for identifying self-decomposing bodies, where the cell nucleus disintegrates, and genetic material seeps into the cells as the cell membrane gradually disappears.

However, this method is rarely used because, generally, the first two DNA identification methods meet most solving needs.

The process of mitochondrial DNA analysis is complex, requiring custom-prepared reagents, with no off-the-shelf solutions, demanding high technical proficiency from crime scene personnel.

In the current forensic lab, Liu Guodong has a higher likelihood of success, while Lu Chuan is the best at it.

Old Bai is essentially not capable, and Yang Sen has a low success rate.

"No worries, start with the conventional method, and only consider mitochondrial if necessary."

This became possible after Lu Chuan established a micro trace evidence analysis lab and upgraded the equipment, enabling mitochondrial DNA analysis, which was impossible with the old devices.

Now, the entire criminal investigation team operates like a precision machine, with every department fully engaged.

Even the stray dogs by the back kitchen are pricking up their ears, sitting at the back door, watching everyone approaching with big, vigilant eyes, as if ready to spot the culprit.

A whole day passed quickly.

The next day at ten in the morning, Qin Yong chaired a case briefing.

Everyone, having stayed up all night, had dark circles under their eyes.

Many middle-aged officers, experiencing split streams during urination, gladly settled in their offices overnight.

The lack of wives and children meant they could smoke whenever they wanted, significantly improving work efficiency.

"I’ll report first."

Sun Jun stood up and walked to the projector: Yesterday afternoon and evening, we investigated, spanning one month, every vehicle that entered the landfill via the ring road."

The culprit must have used some method to dispose of the body, as it couldn’t have appeared in the landfill out of thin air, so if they visited the landfill from North Mountain, they likely passed through this junction.

"There are many vehicles coming from the North Mountain cold storage, but not many exit the ring road at the Warehouse Valley landfill."

"A total of one hundred and thirty-one vehicles, and last night, we determined the drivers’ identities through the traffic management system."

"This morning, I dispatched five groups to investigate these vehicles, hoping for results within two days."

Qin Yong thought for a moment: "The personnel is still insufficient. I reported to the director yesterday, considering the grave nature of the case, city bureau personnel may be drawn in as necessary, prioritizing deploying officers from the police stations to increase staff, coordinating with traffic police, striving to clarify these vehicles in the shortest time possible."

"Yes."

This way, Sun Jun’s team could expedite the investigation process.

"Ren Qiang, how’s your investigation going?"

"We’ve conducted detailed inspections of eleven out of thirty-two cold storages jointly with the fire department under the guise of fire inspections yesterday and found no issues so far."

"Today and tomorrow, we’ll aim to complete the inspection of the remaining cold storages."

"The pace is still a bit slow, staffing as needed, I’ll communicate with the fire department to deploy more people, and strive to complete the remaining 21 cold storages today."

"Yes."

Next was the forensic doctor’s report.

"The body has been in the landfill for over two months, with the death time within this range, but I can’t guarantee whether this body, like the previous one, has a history of being refrigerated."

"The judgment regarding the time of death remains vague."

"Due to the severe damage to the body’s surface features, it’s temporarily impossible to determine the cause of death."

"However, it’s certain that this dismemberment technique is similar to the previous body, and compared to the first body, there’s evidence of improved technique."

The forensic doctor’s judgment provided scarce information but initially established that the perpetrator was likely the same.

"How about the crime scene investigation?"

Qin Yong had already seen the body, which was severely self-decomposed, making it difficult to extract substantial clues from the autopsy.

"The crime scene investigation yielded two findings: first, the box containing the body also had clay from North Mountain."

This point further corroborated the forensic doctor’s judgment that the culprit for both bodies should be the same person.

"Second, just minutes before the meeting started, Yang Sen identified the second body’s identity through DNA analysis."