Diary of a Criminal Investigator

Ren Qiang’s analysis was more specific than the revenge murder speculation put forth during the case briefing.

"Hmm, go on."

"Revenge, lumber mill, skinning, and why did the perpetrator choose to act in the timber storage warehouse?"

"In the lumber mill, all the warehouses are empty at midnight, except for the dormitory."

"Also, Chief, take a look at this."

Ren Qiang picked up a paper and pen from the table: "This is a schematic of the lumber mill buildings. The timber storage warehouse, for convenience in transport, is quite close to the front gate."

"However, the spot where the perpetrator dragged Zhang Xiaofeng over the wall is actually the farthest from that warehouse."

"Why?"

"The chosen spot for scaling the wall was certainly not a random choice. It was likely selected carefully, first to avoid encountering anyone, and second to ensure that the landing area inside the fence was free of spiked boards."

"The killer could have chosen the warehouse on the left of the climbing spot, which stores waste materials and is usually unoccupied. Killing there would be safer, wouldn’t it?"

"So, I believe the murder site chosen by the perpetrator must have a deeper significance."

"So what do you mean?"

"Focus the investigation on the lumber mill workers, especially those who have quit but had grudges with Zhang Xiaofeng."

"Although the killer only left footprints at the scene and no other clues, the entire process exposed how familiar they are with the lumber mill."

"This is definitely not something that someone who had only been at the mill for a day or two could figure out."

This analysis...

Indeed, it’s a direction. In fact, the second action group initially conducted an investigation into the mill workers, but the focus was on current employees, while they only got a list of former employees.

"I agree with this direction. Report any resource needs to me at any time."

"Yes!"

While the action group was pushing forward rapidly with the case, the Crime Scene Investigation office was in a different state.

Old Bai was half-lying on the sofa: "Old Yang, how’s the case on that side?"

The crime scene investigation work takes place immediately after the incident.

Yesterday, throughout the day and night, they had completed all the tasks they could do.

The footprint analysis identified the suspect’s physical characteristics, which was the greatest achievement of CSI.

"Still working on it, but I heard two major leads have now broken down, the case is tough to handle."

Old Yang just found out that Su Xiaogang and Wang Qianqian were not the killers.

"Has Lu’s DNA analysis result come out yet?"

"Should be soon. The hair was found late last night, and we don’t know if it’s Zhang Xiaofeng’s; if not, that would be great."

Old Bai nodded: "Let’s hope. Without interrogation, if there’s a result from the DNA analysis, the case might be directly solved."

"That’s true, but the worry is that the killer’s DNA might not be in the database, which would be troublesome."

It’s impossible for the DNA database to include everyone’s data.

Compared to fingerprint collection, which is simple and widely used, DNA identification is cumbersome and takes longer, making fingerprinting more commonly used in investigations.

DNA comparison is often used only when a suspect’s range has already been narrowed down.

Old Bai had previously encountered a case where the whole town was locked down after an incident, ensuring the killer was within.

The crime scene offered no other findings but one strand of the killer’s hair.

Thus, the police officers in those days conducted DNA collection on tens of thousands of people.

Tens of thousands...

This is the fearsome nature of resolutely solving a murder case.

The suspects never imagine the lengths the police would go to solve a murder case.

"Whether it’s in the database or not, having it is better than not. By the way, are we still on duty today?"

"Definitely have to be on duty. The people from Group One and Two hardly slept last night. If we slept in the office, it’s fine, but going home..."

During investigations, every piece of information reported to Qin Yong or even Ren Qiang isn’t just conjured out of thin air.

A video of a few hours can take one person to digest, and compiling one person’s background information may require another to work overtime through the night.

So, even though it seems like everyone is working step-by-step, they’re actually very busy. This busywork might not directly aid in solving the case but is important for exclusion and selection—tedious and low in perceived value, yet necessary to do.

For others, during times like this, staying to work overtime is essential; no one forces them, but they naturally do it.

See, even over at the forensic team, no one’s gone home; internal female staff are staying at the dormitories. Who dares to leave now?

"Brother Bai, what are you discussing?"

Just then, Lu Chuan had finished the DNA analysis of the hair downstairs, and the result was out.

"Nothing, just the case. How are things on your end?"

CSI doesn’t always turn the tide.

At least this time, Lu Chuan had no major discoveries.

"The hair found at the base of the wall was Zhang Xiaofeng’s."

Old Bai hesitated for a moment, and Old Yang sighed.

No choice, it’s all about luck.

Zhang Xiaofeng happened to lose hair at that time, the killer did not, it’s that simple.

If it were the killer’s hair, it would be just as simple—just a matter of probability.

Liu Guodong had already reported the relevant results to Qin Yong.

Time quickly passed until the next morning.

Ren Qiang, along with Zhang Hui and other elites from Group Two, had already spent a night at the lumber mill.

They talked to each of the thirty-six workers, but to Ren Qiang’s surprise, the earliest any of these workers had come to work was two years ago.

About earlier matters, such as who Zhang Xiaofeng had hired before, any past grudges, or anyone who had conflicts with Zhang Xiaofeng, these workers uniformly claimed ignorance.

"This issue... I think you could ask President Zhang’s wife."

The guard hadn’t been around long and didn’t know much about earlier matters: "I heard President Zhang’s wife was around for quite a while when he first opened the mill; she must be familiar with earlier events."

In the afternoon, after gathering all information, Zhang Hui keenly detected a problem.

"Brother Qiang, there’s an issue with the recruitment timeline for the workers here."

Ren Qiang also noticed that some of the current workers at the lumber mill were hired two years ago, and some over the past year or so.

Logically, with Zhang Xiaofeng’s lumber mill running for five years, there should be older workers, right?

So, what led to the old workers leaving?

An hour later, Ren Qiang and Zhang Hui met Zhang Xiaofeng’s wife.

When asked why there were no old workers, Zhang Xiaofeng’s wife’s expression changed suddenly.

"That... the event back then was... so embarrassing, I..."