Chapter 1300: Upstream and Downstream

Changyang Vocational School of Technology is located in the southern suburbs of Changyang City. It is neither Changyang, nor technological, nor vocational, and it doesn't even look like a school.

The campus management is quite strict; facial recognition is required for entry and exit, and attendance is taken for classes, but the pressure is not as great as in high school, and the density of students is slightly lower.

Cao Chujun specifically brought two female police officers to visit the school, going through the dormitory, classroom, classmates, friends, and teachers of the deceased Zhang Xianyao.

At the same time, the cyber security team began to check Zhang Xianyao's mobile phone and laptop. From WeChat to browser history, they wanted to turn everything over. The supporting image investigation team, without waiting for Jiang Yuan to mobilize them, took the initiative to start collecting surveillance records from the surrounding area. The grandfathers of the technical investigation team also rarely looked easy to talk to; they only needed the Criminal Investigation Detachment to file a report, and they started working without a word, without the pushing and pulling, the hesitation of the past.

The intensity of investigating a homicide case versus an unnatural death case can be said to be like taking the Tsinghua entrance exam without preparation versus being an art student on a sponsored program.

An unnatural death might just be a matter of two or three police officers writing a report, but once it is discovered to be a homicide, resources from all aspects will converge.

Even for a crime of passion where the suspect turns themselves in, the evidence and materials that need to be collected are not a single bit less.

The suspect decides to turn themselves in now because of emotional factors, but that doesn't mean they won't retract their confession once they enter the detention center or reach the court. Even after entering prison, the prisoner can write to the prosecutor of the correctional facility. That might be two years later, three years later, or even ten years later. By then, let alone whether the investigating police officers still remember, old criminal investigators like Cao Chujun might have already retired.

In the end, the only thing that can transcend time is paperwork.

On the contrary, regarding the problem of solving the case, everyone didn't feel there were too many difficulties.

Let alone that Jiang Yuan is here now, even without Datuk Jiang, Cao Chujun felt he had the ability to solve this case.

Of course, the difficulty of drowning cases is generally relatively high, but his, Cao Chujun's, ability to solve cases is also higher than average.

Previously, the police officers at the police station thought the deceased died accidentally from wild swimming, so it didn't enter the homicide process at all. Now that the Third Detachment of the Criminal Investigation Detachment has taken over, this is an elite team for investigating difficult and major cases. Investigating a case of intentional injury resulting in death (drowning) isn't something they can just...

"Can't handle it." After Cao Chujun returned from Changyang Vocational School of Technology, he let out a sigh.

He is a veteran, and he didn't feel embarrassed when saying this. He just spread his hands and said: "He's just an ordinary little kid, doesn't even have a girlfriend. Let alone a girlfriend, he doesn't even have an ex-girlfriend, doesn't even have a crush! What's wrong with young people today?"

His deputy also said: "The kid doesn't have money either, and his relationship with his classmates is neither good nor bad. It feels like he doesn't even have a particularly good friend, at most just roommates or classmates eating in the cafeteria together or something. There's no reason to be murdered."

"That's why the police officers who investigated earlier thought it looked like a wild swimming accident." Liu Jinghui sat in the office, not in a hurry, and said with a smile: "Now there is clear evidence proving that the deceased was beaten before death, so we have to consider what caused the injury. Was it premeditated, caused by the situation, or... an accident?"

Cao Chujun couldn't help but laugh: "You've said it all. However, for a 17-year-old boy, the only reason he could be murdered is love. If we talk about money, the money he carries might not even be as much as a food delivery rider."

"Hmm... however, random murder or robbery should still be considered last." Liu Jinghui ended Cao Chujun's probing with one sentence.

The investigation route of a special task force cannot always use the exhaustive method. As long as it is possible, everyone should still use intelligence and evidence to rule out unsuitable routes and then concentrate resources on reasonable routes.

At such times, investigators also need to understand the thoughts of the person in charge of the special task force.

For example, whether to consider the robbery-murder route, or whether to focus on the robbery-murder route.

Because this route is the most difficult to handle, and the cost might also be the highest—of course, different investigation strategies will bring different costs. The common investigation idea for robbery-murder is still to consider the situation of recidivists, often using special informants or looking for stolen goods.

Like the deceased Zhang Xianyao's mobile phone, it wasn't found. It's possible it fell into the Taihe River, but if it can be linked to a certain fence, it can be suspected as robbery. Of course, it's also possible that someone else picked up the phone. Then we have to ask why the deceased was separated from the phone, where it was picked up, when it was picked up, and especially why the phone was turned off in a certain place.

Liu Jinghui obviously wanted to choose the way of investigating from easy to difficult.

This is nothing strange; most special task forces have and only have this choice.

Opening multiple investigation directions at the same time requires costs, not just the problem of investigation resources, but also a large amount of personnel input. If it can be investigated clearly simply—most homicide cases now are actually like this. Then, investing a huge amount of preliminary expenses in one go is a bit too "bold."

However, Cao Chujun was probably a bit inclined towards robbery-murder, which is why he asked Liu Jinghui this way.

He also started from his own experience, because apart from robbery and similar accidental conflicts, Zhang Xianyao had no reason to be murdered.

On the other hand, it is because the special task force led by Jiang Yuan absolutely has enough resources to open a multi-threaded investigation, and regardless of whether it is necessary, no one will nag.

This is like a child who is the top of the grade in a provincial key school. He asks to hire a few more subject teachers for tutoring, or even asks to hire a few more teachers for a certain subject. Will anyone object? Will anyone discuss the waste of tutoring fees?

Thump.

Jiang Yuan pushed the door and entered, covered in dust.

"How is it?"

Jiang Yuan and Liu Jinghui asked each other in unison.

"Then let me describe our current progress first." Liu Jinghui then briefly described today's investigation, and Cao Chujun also added a few sentences on the side.

Jiang Yuan listened and nodded, saying: "I walked through the river section near the school of the deceased. I let the laboratory take an electron microscope photo of the diatoms I fished up for me to see. It basically confirmed the location where the deceased fell into the water."

As he spoke, Jiang Yuan looked for it on the map hanging on the scene, and then drew a circle with a red pen.

"Two kilometers downstream from the school." Jiang Yuan said, marking the specific location and distance on the edge of the circle.

The newly acquired skill is still very easy to use, saving the laboratory from acting as an intermediary. If he does it himself, he naturally doesn't have to wait so long.

Cao Chujun immediately turned around, picked up a report, confirmed it, and said: "This location does not match the location of the mobile phone positioning. The last positioning location of the mobile phone signal was near the school..."

Mobile phone positioning was also taken after the special task force was established. Previously, it was determined to be an unnatural death rather than a homicide, so they wouldn't and couldn't call on the resources of technical investigation at all.

Jiang Yuan only gave a light "Hmm" and said: "The mobile phone and the person were separated, more than 2 kilometers apart, which further shows it wasn't wild swimming. There is no surveillance at the drowning point. Check the surrounding ones, and see if there are any recidivists among the people overlapping with the mobile phone, and if there are any people the deceased knew... are there any eyewitnesses?"

"Someone saw Zhang Xianyao leave from the south gate and go towards the river channel. A couple walking near the river channel also saw him, and after that, there was nothing." Cao Chujun said.

"Did he go upstream or downstream?" Liu Jinghui interjected.

Cao Chujun hurriedly went to check, then said: "He went downstream."

"There are conditions for wild swimming downstream. Theoretically, if he was going for wild swimming, he could leave his mobile phone in the dormitory, but to avoid the trouble of entering and leaving the campus, it is also very reasonable to deposit it in a shop outside the school." The probability of what Liu Jinghui said is not high, and there are many prerequisites, but it is a proposal that is beneficial and effortless. Two police officers can solve it by asking.

Cao Chujun immediately agreed and said: "I will let people visit these shops by the way to see if anyone has seen Zhang Xianyao."

"Also need to visit the students in the school. Students from surrounding schools and residential areas can also be asked. Zhang Xianyao's nasal bridge was broken, and his brow bone also had a fracture. This is not easy to do; it takes some strength and courage." After thinking, Jiang Yuan continued to arrange.

?? There is an event in the afternoon, an exchange between China Literature Group and the uncles from the Pudong Cyber Security Bureau. I am attending as a guest to see if I can trick a few stories out of them.

? (End of chapter) ===== CHAPTER 1301 =====