Diary of a Criminal Investigator

An extensive investigation was launched based on this.

Although the case is handled by the provincial serious crime unit, it actually occurred in Tianzhou City, so the city’s Public Security Bureau cannot shirk responsibility. Such a massive investigation is certainly based on the strength of Tianzhou City Public Security Bureau.

Before starting, Li Donglin was conducting a motivational meeting.

"While the main investigative force is the Tianzhou City Public Security Bureau, you few must take responsibility."

"Given the current situation, the killer likely lived on Nanshan Road in their early years and later moved to Northern Avenue. This investigation will focus on Northern Avenue to ensure a 100% thorough search, with no omissions, especially those who moved from Nanshan Road to Northern Avenue."

Wang Song, Song Mingguang, and others are veterans in this regard. Even without Li Donglin’s instructions, they understand that the success of this investigation could potentially determine whether the case can be solved.

As for Li Donglin’s requirement of 100% thoroughness without missing anything, achieving this is actually not difficult.

Based on the local police station and neighborhood committee, concentrating forces to figure out the residents on a street is actually not difficult.

As for the residents, there’s nothing to say; neighbors know each other somewhat. Even the mobile population is relatively easy to investigate.

Whether people in the mobile population are renting or working on Northern Avenue, they must have a landlord or a boss.

Once you have a lead, it’s easy to find.

Especially considering that the crime spans over 10 years, it’s unlikely that the suspect is a transient.

The suspect not only can’t be a transient but also needs a relatively stable place to handle the disposal of bodies.

They need dismemberment tools that are not easily detected.

Renting a place to do such things... unlikely.

The difficulty lies in the precision of the investigation.

Last year, in Hang City, there was a bizarre murder case. The wife disappeared at midnight, with no sign of life or death.

With the wife missing, naturally, the husband was the first suspect. However, despite several rounds of investigation, interviews, and inquiries, the wife’s husband never gave away the slightest clue.

Later, although local police had clues, they couldn’t confirm it was the husband who killed her due to the lack of the victim’s body.

Not until the police dredged the residential area’s sewage septic tank for several nights and found some residue, confirming it was human tissue, combined with the spike in water usage on the night of the wife’s disappearance, did they eventually pinpoint the husband as the suspect.

From this case, it can be seen that searching for suspects is not as simple as finding a person and discovering they are the killer.

No one has "murderer" written on their forehead.

The hardest part of the investigation is identifying suspicious clues.

"Additionally... ensure your safety. Since the suspect has killed so many people, we can say they are extremely vicious. Whether they have lethal weapons, no one knows, so vigilance must be increased, and absolutely no one should act alone."

Li Donglin has gone through such situations. Five years ago, he participated in a vicious case supervised by a ministry.

Due to a shortage of personnel, the local police splitting investigation pairs intended to be at least two to one person per group.

One police officer discovered the suspect during an investigation. The police officer was not in a hurry to act and planned to return for reinforcements.

The suspect seemed aware of being exposed, and as the officer turned to leave, they were ambushed from behind and struck in the neck with a kitchen knife.

Conducting investigations in pairs is a lesson paid for with blood and life.

"Don’t worry, Director Li, we’ve all experienced it and will never make such a rookie mistake."

Not just Wang Song and others, even the youngest and least experienced field officer, Lu Chuan, won’t act in such a way now.

Unless necessary, one should not impulsively harbor heroic inclinations, which endanger oneself and others.

Of course, there are no absolutes in the world. Unless necessary, one should preserve life, but sometimes, wearing the police uniform means you can’t retreat even if you want to.

When two opposing forces meet, courage wins. Many times it’s one-on-one, and if you don’t go, no one will.

Sun Jianguo, an old policeman from the People Road precinct in Tianzhou City, is 59 years old this year, with just one month and three days until retirement.

Northern Avenue falls under the jurisdiction of the People Road police station.

"Old Sun, you shouldn’t take up this task. You have just over a month until retirement. Do some desk work and don’t go on field duty."

The People Road police station of Tianzhou City Public Security Bureau has an unwritten tradition: officers with less than three months until retirement are not assigned to field duties.

"Director Chen, I know you’re looking out for me, but isn’t the precinct busy? Short on manpower, it’s not a big deal to participate in such a big case like this, just doing an investigation isn’t a problem."

Chen Jiang remained slightly silent; the rule wasn’t set by him but by his predecessor.

As for why...

It’s a lesson left behind by lives lost.

Fifteen years ago, the People Road police station had two old officers—one had two and a half months, and the other had ten days until retirement.

There was also an investigative case then, and the two went to investigate together only for the suspect to blow up a boiler room, and neither of them made it out alive.

And those two officers had been with the People Road police station since its inception. You could say they built up People Road police station.

Most of the young people in the station were trained by them.

So, to commemorate the two, the then-station director left behind this unwritten rule.

Sun Jianguo evidently saw through Chen Jiang’s hesitation. When this incident happened, he was one of the many apprentices of those officers.

"Alright, alright, I won’t cause you trouble. The Old Street, I’ll go with Erhe to the Old Street."

Hearing Sun Jianguo wanting to head to the Old Street, Chen Jiang’s expression relaxed.

The Old Street at People Road is actually a small alley, the early form of People Road, the entire People Road developed with Old Street as its center, and Northern Avenue is one of its main streets.

Due to its basic infrastructure, only old residents of People Road live there, totaling just about thirty households, all known to the precinct members.

Sun Jianguo himself moved out from the Old Street in his early years; no one knows the people better than he does.

Erhe’s full name is Zhang Erhe, Sun Jianguo’s original neighbor, a big and strong man, now an auxiliary police officer once fond of Sanda, considered a skilled practitioner, and even considered the precinct’s combat champion.

With him there, and at the Old Street, there will certainly be no problem!

"Third Uncle, is it necessary to go to the Old Street?"

In the precinct, there’s no hierarchy. Seniors are called brothers or sisters.

However, the relationship between Zhang Erhe and Sun Jianguo is different. Zhang Erhe’s father and Sun Jianguo were childhood buddies, and you could say Sun Jianguo watched Zhang Erhe grow up.

Later, when Zhang Erhe joined the precinct as an auxiliary officer, it was at Sun Jianguo’s recommendation.

It’s not a secret; everyone in the precinct knows it, which is why Zhang Erhe calls Sun Jianguo "Third Uncle."