If the identity of the deceased cannot be determined, it is impossible to advance the case by investigating the deceased's interpersonal relationships. Moreover, the murderer abandoned the naked corpse, obviously because he did not want to reveal the identity of the deceased through information such as clothing.

As for ID cards, mobile phones and other items, they must have been hidden or destroyed by the murderer long ago. From this point of view, the murderer acted very cautiously, and the result was clearly successful.

Lu Chuan thought for a while and looked at Yang Sen and Lao Bai: "Brother Yang, they have collected some footprints outside the wall, I want to try to analyze them first." ”

"Also, the murderer is throwing the body over the fence into the Qinghe Amusement Park, and I think I can do some data analysis." Footprint analysis, Liu Guodong knows that Lu Chuan is also good at this.

However, the clarity of the footprints collected this time is very poor, and there are multiple footprints superimposed on each other.

Moreover, according to Zhang Hui's preliminary visit near the scene of the crime, the time when the murderer dumped the body should have been between 11 o'clock in the evening and 6 o'clock in the morning yesterday.

Because the last time Zhang Fugui patrols the field every day is 11 o'clock in the evening. According to Zhang Fugui, he used a strong flashlight to patrol the field at night, and took a look at the corners and corners of the places he couldn't go.

Where the body was lying, Zhang Fugui was very sure that when he patrolled the scene at eleven o'clock last night, he didn't find it.

This established that the earliest time for the murderer to dump the body last night was 11 p.m. As for the early morning time, it is because around six o'clock in the morning, before dawn, there are already old people walking in the small garden for morning exercises.

If the other party dumps the body during this time period, it is easy to be found. When the body was abandoned, it was scraped against the wall and blood flowed out, and then it was frozen and stiffened, and the murderer must have thrown the body after eleven o'clock last night and before six o'clock this morning.

When Lu Chuan and others arrived at the scene, it was already 10 o'clock in the morning. I don't know how many people have walked on the path outside the wall.

Even if the murderer really left footprints, after being trampled by many people, it was difficult for Lu Chuan to analyze the results.

"Footprints...... Try it first. Liu Guodong obviously knows the difficulty here: "What do you mean by data analysis?" ”

"That's right," Lu Chuan opened the survey notes he had just recorded at the scene: "The height of the fence at the construction site of Qinghe Amusement Park is two meters. ”

"The deceased was about 1.63 meters tall and weighed about 55 kilograms."

"If the murderer wants to climb over the fence with such a corpse, he can first be sure that the murderer is in good physical condition."

"And the height of the murderer's arm should be at least higher than the fence, which is two meters and two." The specific height of the fence has been carefully measured by Lu Chuan at the scene.

Lu Chuan stretched out his arm and signaled: "The length of a normal person's arm is more than forty centimeters above the top of the head. ”

"In this case, the murderer's height is at least about one meter eight."

"He is 1.8 meters tall and has good physical strength, and the murderer's gender can basically be locked as a male."

"Also, I'd like to do a trace physical evidence collection on the corpse pair." Trace evidence collection?

"Are you sure?" The reason why Liu Guodong raised this question is because it is not easy to collect trace physical evidence.

The so-called trace physical evidence is actually extremely small criminal evidence. Theoretically, any contact between two objects will leave a certain trace.

For example, clothes stick to pollen, palms touching pigments, etc., there will be obvious contact marks. And there are some contacts, the traces will be very inconspicuous, for example, the magnet touches the iron, and there is no trace on the surface after separation, in fact, there must be a molecular structure on the magnet.

It's just that the molecules are so small that they are invisible to the human eye, and they can't even be distinguished with special magnifying instruments.

But contact is real. The order of magnitude of trace physical evidence in forensic identification is obviously much larger than that of molecules.

Common trace evidence includes pollen, hair, dander, fibers, cosmetics, and more. It is not only difficult to collect trace physical evidence, but also difficult to analyze and identify.

For the identification and analysis of trace physical evidence, there is a special skill card among the skills provided by the Luchuan system.

Different from the general physical evidence detection and analysis, the identification and analysis methods of trace physical evidence are different, and the instruments used are also different.

The Haizhou City Criminal Investigation Detachment itself does not have the ability to do trace physical evidence identification and analysis. Even, the Technical Appraisal Center of the Haizhou Municipal Public Security Bureau does not have such people and equipment.

In the province, only the provincial capital public security bureau and the provincial department technical appraisal center have trace evidence identification laboratories. In other words, after Lu Chuan's collection is successful, the collected trace physical evidence will be sent to the provincial department for testing.

"There is not much of a problem in the collection, that is, in terms of identification and analysis, the Qin team needs to apply to the provincial department." Lu Chuan has intermediate field investigation skills, and it is no problem to do general trace evidence collection.

"Okay, you do a footprint analysis first and see if you can get results, trace physical evidence...... I'm going to ask for instructions from the Qin team. After Liu Guodong left, Yang Sen and Lao Bai came over.

"Xiao Lu, have you studied trace physical evidence?" Yang Sen and Lao Bai were both transferred from front-line investigators to the current investigation.

Most of the methods used are old methods and routines. In recent years, due to the improvement of the technical level, there is a possibility of collection, identification and analysis of trace physical evidence, but it is not very good.

But I've heard of it, and I've done some training in this area, but the results are mediocre. Lu Chuan nodded: "I've learned some, anyway, there is no other way now, just try it, as an accumulation of experience." "Hmm.

Lao Bai nodded affirmatively: "What are you doing, like forensic doctors, you have experienced more scenes, more corpses dissected, and more people have seen." Janssen couldn't agree more.

Why don't the police stations below and even the criminal police brigades in the districts and counties have full-time criminal police officers on the spot? Can't afford it, of course not.

The reason why the criminal police brigade or police station below does not have a full-time criminal police officer for on-site investigation is because there is not enough case training for on-site investigation.

Just like the Haizhou City Criminal Investigation Detachment, there is no full-time trace inspection, not because they can't afford it, but because Liu Guodong is enough.

The reason why the Tianzhou City Criminal Investigation Detachment has a full-time on-site investigation and a full-time trace inspection is because Tianzhou City has a large population and many cases, so it can have enough work

"Cultivate" full-time on-site investigation and trace inspection.

"This time, the two of us will help you and learn this trace physical evidence." In his position, he must seek his own government. Although Lao Bai will retire in one year, his ideological consciousness is very high, and the opportunity to improve his business skills cannot be missed.

While waiting for Liu Guodong to come back, Lu Chuan seized the time to analyze the footprints collected by Yang Sen and Lao Bai.

However, just like Liu Guodong worried, the footprints were too chaotic, and more than a dozen shoe prints were superimposed, and it was impossible to distinguish them at all.

Lu Chuan used some of the abilities in advanced fingerprint identification and analysis, but there was nothing he could do about it. Half an hour later, Liu Guodong returned to the survey office: "Xiao Lu, the Qin team has agreed, he will apply for it from the provincial department, and then it will be up to you." ”