Diary of a Criminal Investigator-Chapter 349: Suddenly Got Busy

Crime Scene Investigation office.

Lu Chuan’s fingerprint comparison work also reached a critical moment.

Extracting fingerprints from rebar is inherently difficult, and the grassroots police officers involved in the case were not particularly skilled, which led to issues in the extraction itself.

This time, Lu Chuan not only improved the clarity of the fingerprints but also completed them.

Because of the special structure of the rebar, the killer left fingerprints only on the protruding parts, not the recessed areas.

Completing the fingerprints involves connecting each ridge line, a task that is quite labor-intensive, taking Lu Chuan over three hours to basically finish.

Focusing so intently and expending so much energy on a single fingerprint—Lu Chuan only spends this kind of time when dealing with a murder case.

Moreover, the environment is special, and there was no interference, allowing Lu Chuan to focus on his work alone in the underground lab.

If he were in the upstairs Crime Scene Investigation office, such meticulous and concentrated effort on a fingerprint would be very difficult.

The system was conducting fingerprint comparisons.

Due to the extremely fragmented state of the fingerprints, Lu Chuan did not use the complete comparison method this time.

Instead, he used the similarity comparison method, where the fingerprint system lists those with the most shared characteristic points with the target fingerprint.

Then Lu Chuan manually analyzes and compares each fingerprint.

This manual analysis comparison is actually about using the peculiarities of the characteristic points for exclusion.

The target fingerprints in the system are not all relatively complete; the fingerprints in the database can actually be divided into two categories based on identity information.

One category is those with confirmed identity information, where the basic information about the owner of the fingerprint is known.

Most of these fingerprints are collected through two channels: officially, by police officers, or from individuals with prior criminal records when apprehended, etc.

The other category is those where the identity information of the fingerprint owner is not confirmed; the system only has fingerprints, with identity information left blank.

This is generally a possibility where a crime was committed, a fingerprint left at the scene, but the fingerprint information was not entered into the system through official channels.

In this case, it’s akin to waiting by the tree for a rabbit.

You never know when scanning will catch them, successfully match, and capture them.

Another use is merging cases; criminals rarely offend only once.

Take, for example, the uncle at the alley playing with the young ladies—how likely he’d only go once?

The uncle is like this, and so are the young ladies.

Suspects are the same.

Because that’s human nature.

Excluding unique fingerprints is relatively quicker.

Lu Chuan quickly ruled out all twenty fingerprints in the first round given by the system.

Flipping to the next interface, there were another twenty fingerprints.

The system provides similar fingerprints with sorting based on similarity from highest to lowest.

But high similarity doesn’t necessarily mean a match.

Low similarity doesn’t mean it can’t match.

Lu Chuan rarely uses this method, but compared to complete comparison, similarity comparison is what many Crime Scene Investigation detectives adopt.

After all, this method requires less preprocessing of fingerprints.

The twenty-third fingerprint received the longest observation from Lu Chuan.

"No peculiar points... You’re the one!"

Similar fingerprints given by the system don’t differ much; the similarity between the first sorted and the 30th, 40th fingerprint with the original has some probability.

Sun Tao, male, thirty-two, local to Haizhou, had been previously imprisoned for various crimes such as fighting and brawling, theft, robbery.

This was the owner information for the twenty-third fingerprint.

Lu Chuan stretched, Zhang Fengzhi’s case was considered solved.

Although Zhang Fengzhi himself was not a good person, solving a case isn’t about whether the victim is a good or bad person.

Moreover, there aren’t so many good people in the world—everyone has done one or two bad things.

Good and bad in people often have duality; a killer isn’t necessarily a bad person, and the murdered not necessarily good.

Lu Chuan had seen more than one case where an honest person, driven to the edge, resorted to desperate measures. 𝘧𝓇𝑒𝑒𝑤ℯ𝑏𝓃𝘰𝑣ℯ𝘭.𝘤ℴ𝘮

In Lu Chuan’s view, the hardest part of working in the judicial system should be the judge’s sentencing.

Some laws set a range for the sentence, like 3 to 5 years.

Three years is manageable, with mitigating circumstances it can be sentenced to three, five years is also manageable, with serious circumstances it can go the maximum of five.

Mitigating or serious circumstances are clearly defined by law, and the submission of these circumstances for judgment isn’t done by judges but by the agencies handling the case reporting to the court.

But under what circumstances it can be sentenced to four years—that’s debatable.

Usually, other cases are taken as reference for sentencing, but what if there are no other cases to reference?

Judges are also human, and humans have emotions.

Fortunately, from Lu Chuan’s perspective, it’s just technical work: confirming fingerprint identity and sending it out, the action team will naturally be there to apprehend the suspect.

Ren Qiang had just finished communicating with the Liangzhou City side, confirming the suspect had been successfully captured, bringing great relief and happiness.

His anxious heart finally settled.

A case involves many stages: case reasoning, evidence collection, crime scene investigation, etc.

Each of these stages has its own challenges, but for Ren Qiang, capturing the suspect is actually the simplest.

Because this stage is tangible and visible, usually many against a few.

Except for extremely rare fierce bandits, many suspects resemble lambs led to slaughter when apprehended.

An adult, even with a weapon like a dagger, facing a dozen heavily armed strong men wouldn’t feel secure.

Submitting without resistance is the choice for many suspects.

Knowing they can’t escape, forced struggle leads only to harm.

After the call, Ren Qiang didn’t have time to return to the command center, he directly instructed the driver to turn the car: "Go to Friendship Road police station."

People with criminal records, especially those recently released or habitual offenders, although they don’t have tracking devices, are among the three key personnel monitored by the local police station.

Though they can’t know what these people are doing every day, they must periodically conduct checks, ensuring these people won’t commit major crimes.

Of course, when the police station is busy, they can’t always keep track.

No one is anyone else’s parents; they can’t watch you every day.

If trouble arises again, they’ll just apprehend and send them in for re-education.