Diary of a Criminal Investigator

For example, is there a possibility that the other people went to the bun shop run by the fifth victim to eat buns?

Or, could these people have visited the massage parlor where victim number one used to work?

Or perhaps went to the street stall where the fourth victim repaired bicycles?

Or even taken a ride in the taxi driven by victim number three? Given that so much time has passed, it’s hard to say for sure.

Of course, whether these people have connections is both important and unimportant.

What’s important is that in many past murder cases involving multiple deaths, the perpetrators were found through the relations between the victims, which helped in solving the case.

Saying it’s not important requires detailed analysis of each specific case.

Take the current case, for example. The five victims were all engaged in jobs with significant human interaction, making it entirely possible that the murderer was familiar with just one of them.

"I have a thought..."

Wang Song reported the basic details and mentioned a case.

"Twelve years ago, our bureau handled a case where the murderer killed three people and buried them in his backyard."

"He wasn’t particularly familiar with the three victims, nor did he have any deep-seated hatred toward them; it was just some temporary quarrel that led to a surge of emotion causing the murders."

"Now in this case... I wonder if there is a similar possibility?"

"That the murderer didn’t kill due to any particularly strong motive, but rather acted on impulse or a trigger point for the victim’s reflex reaction?"

Wang Song’s idea...

Li Donglin somewhat agreed; although it couldn’t be said for sure, it seemed possible now.

"Lu Chuan, have you found anything?"

Lu Chuan had been assisting, or rather leading the forensic analysis of the bodies over the past few days, especially in identifying the deceased, making enormous contributions.

It’s fair to say that the very reason they had so many hypotheses and the basic direction for field investigation was the identification of the bodies.

Over these few days, Lu Chuan’s work extended beyond just this; he had another crucial task.

Trace evidence analysis.

"I’ve collected trace evidence from all five boxes. This morning, Haizhou City sent over the analysis results."

Although Tianzhou City had relatively advanced criminal investigation equipment, it was only advanced compared to other municipal investigative teams.

Purely in terms of hardware, Haizhou City’s criminal investigation team outperformed all municipal bureaus, protecting the provincial capital.

With a billion yuan invested, not every team had such a generous donor.

Hence, only two trace evidence analysis labs existed: one in the provincial department, and one in Haizhou City’s criminal investigation team.

Yang Sen worked overtime for three days to finish analyzing everything Lu Chuan sent over.

Liu Guodong and Old Bai wanted to swap shifts with him, but as his son had just finished high school exams, Yang Sen preferred not to return home.

Going home for what, cooking?

Mopping?

Doing laundry?

Getting scolded?

No thanks, there’s not even a place to smoke, it’s more relaxing to work overtime at the office.

For middle-aged men, continuing a marriage without the binding of children is already being a good man.

"The boxes containing the bodies vary in shape. I checked the box brands these past days; they are mostly knock-offs that are easily found in marketplaces."

"However, they’re all of good quality. All the boxes are made of genuine leather, likely prepared by the murderer to prevent the river water from soaking in, causing the boxes to rot and exposing the remains inside."

Li Donglin nodded; this clue mainly started from the box material... genuine leather.

These days, many sell boxes, but those selling genuine leather boxes are rare.

Yet, up till now, there’s been no valuable lead.

Tianzhou City has at least eight hundred to a thousand vendors selling genuine leather boxes.

"The key is the sediment inside the boxes."

The trace material analyzed by Haizhou City mainly consisted of the sediment inside the boxes.

"Although the boxes were fairly sealed, over time, some river sand still entered the interior of the boxes."

On the projector, there was the trace evidence analysis report.

The sediment Lu Chuan collected was consistent in composition with that of the riverbed in Wang Family River.

Soil composition is extremely complex, consisting of various particles, organic substances, minerals, water, air, microorganisms, etc.

Soils from different regions exhibit rather distinct regional characteristics.

For instance, some areas might have clay soil suitable for pottery, some areas sandy soil with good breathability, and others black soil rich in microorganisms and minerals optimal for growing crops.

Furthermore, soil color varies significantly across regions: loess, black soil, red soil, brown soil, etc.

"Besides the sediment from Wang Family River’s riverbed, we made two other discoveries."

On the projector, the five body box numbers were displayed.

"In boxes one, two, and five, we found a type of highly adhesive soil."

"In boxes three and four, we discovered another type of sandy soil substance."

As Lu Chuan gave his report, Li Donglin’s expression was extremely solemn.

This information had just arrived that morning, and it was Li Donglin’s first time hearing it.

"Dismemberment at two different locations?"

The detectives present were all heavy crime team members selected by the provincial department, and none of them were slackers.

Once Lu Chuan’s analysis was presented, everyone understood its implications.

The time of death for bodies one, two, and five was within a year and a half, specifically eight months, one year and three months, and two months.

However, the time since death for bodies three and four was much longer at eight and fourteen years ago, respectively.

Lu Chuan nodded to Song Mingguang’s suggestion: "We have already reached out to Tianzhou City’s geological department regarding the soil from both locations and should soon determine their origins."

Decades ago, every local geological department had already thoroughly analyzed the soil in their locale.

Of course, the smallest unit division, in the absence of special terrains such as mountains, lakes, or hills, is based on towns.

"This result... it would seem the murderer might have moved house at some point?"

He likely lived in one place during the murders of bodies three and four, and in recent times, when he killed victims one, two, and five, his place of residence had changed.

This explains why the soil composition in the boxes varied.

"Additionally..."

Lu Chuan switched the projection to a map of the nearby township areas.

"The areas where the five murder victims lived... appears quite peculiar..."

On the projected map, five red dots lit up sequentially, representing the precise geographic locations where the five victims disappeared.