National Forensic Doctor

"I also want to look at the evidence again. Let's review the papers first."

Jiang Yuan did not start the lecture directly because of the public's attention. The backlog of cases eleven years ago was a real backlog, and the grading work alone was quite arduous.

Now, since there is already a formal special team for backlogged cases and a team of twenty or thirty people, instead of just a few people silently tinkering, Jiang Yuan wants to be more formal.

The first step in restarting the backlog is to sort out and sort out the clues.

Clues from the past must be brought out, and if there is evidence that can be used for non-destructive inspection, it must be re-examined to see if the latest technological innovations can play a role. We should also look at the evidence from that year to see if there are any errors, omissions or imperfections.

And the information that the police were looking for previously needs to be read by someone. There are hundreds or even thousands of pages of inquiry transcripts that need to be read by someone. If they can find clues or some supporting evidence, that would be even better.

To a large extent, "the case will not be withdrawn until the murder is solved" is still a gimmick. However, it is indeed very necessary and even smart to leave one or two policemen on the task force to know the whole process.

On the "Backlog of Cases Task Force" side, the two policemen from the task force contacted, the older one has retired, and the younger one... is still an ordinary policeman from the criminal police detachment. They can catch up with the progress if they are pulled over on site.

When everyone was busy, Liu Jinghui sat next to Jiang Yuan and whispered: "You feel it too, right?"

"Feel...what?" Jiang Yuan looked confused.

"This case is different from others." Liu Jinghui looked solemn.

Jiang Yuan's expression suddenly became solemn: "You mean, it's possible..."

Jiang Yuan pointed upward with his hand, his eyes full of questions.

Liu Jinghui was stunned, stretched out his hand and took out another finger from Jiang Yuan, and said: "What I mean is that this may be a male and female robber. Well, it is not accurate to say that the robber is a man and a woman. The suspects should be a man and a woman. .”

"Hey, why?"

"Because there is no ***." Liu Jinghui's voice was low.

Seeing that Jiang Yuan was still puzzled, Liu Jinghui coughed twice and said: "This... I have done several taxi robbery and murder cases. I have also studied some cases inside and outside the province. Let's put it this way, if the taxi driver is The female driver drove into the wilderness. If there is robbery or murder in the end, most of them will involve ***."

"The majority, not all."

"For those that do not involve police, either the female driver is too old, or there are women in the gang. The rest, many of them will turn into robberies and murders." Liu Jinghui sighed: "So, this case There were obvious omissions during the on-site investigation.”

This is why Liu Jinghui gave this case a high score.

Jiang Yuan listened quietly to the explanation.

"I looked at the photo in the file. There was a long hair in the back seat of the car, but I found the evidence bag and didn't take any samples at the beginning. I guess the criminal police investigating the scene thought it was the victim's hair and looked at it. It does look like it, but I think it's more likely to be the murderer's hair.

Liu Jinghui said as he found the photo from the file.

There is a blood stain in the gap of the brown seat. The photographer wanted to take a picture of the blood stain, but a long hair can be vaguely seen next to it.

Jiang Yuan immediately took the victim's photo for comparison. After repeated judgments, he nodded slowly: "It's possible that the hair is somewhat similar to the victim's. The length and color are similar, but the curl is slightly different. The condition of the photo is too poor. , we can’t be sure, but even if it’s not the victim’s hair, it’s possible that it was left by the previous guest.”

Regarding the taxi case, the annoying thing is that the vehicle seems to be a treasure trove of evidence. When you open it, the ownership of each treasure is problematic.

In the process of extracting evidence, how to extract evidence and what evidence to extract is itself a test of current investigation.

First of all, it must be clear that it is impossible to provide unlimited evidence through current surveys.

Evidence bags cost a few yuan each, which is nothing. DNA reagents are indeed not cheap. The current price of domestic products is a hundred or ten yuan. Moreover, there are always some imported products that are easier to use than domestic products. You want higher accuracy. , better sensitivity, always comes at a price.

A murder scene, extracting more than a dozen

It is normal for DNA traces to be found in hundreds of places, and it is normal to extract hundreds of places. However, in such a large scene, it is impossible to extract everything from hundreds of places.

And this is not only a matter of expensive consumables, but also the workload of the laboratory is limited. A municipal bureau's DNA laboratory processes DNA testing materials all day long, and the feedback time for ordinary cases is only on "weekends" and "next week".

Although murder cases are taken seriously, they cannot occupy unlimited resources.

Investigators or other technicians, or other criminal police officers, always have to make some judgments and choices based on their own experience.

Obviously, judging from the circumstances of the case, the police officers who participated in the investigation of the scene at the time may not have thought that a woman would be involved in such a violent robbery and murder case of beheading. Therefore, when collecting the materials for examination, this hair was not specifically detected.

Liu Jinghui said noncommittally: "I guess it was a man and a woman. Another reason is that there was only one bloody footprint at the scene. Moreover, the DNA extracted from the victim's fingernails has not been matched for many years. This kind of stability, It’s also very rare, I bet it’s a pair of desperate couples.”

"Do you think the killer would have committed another crime?"

"Most of the murderers who commit robberies and murders are repeat offenders." Liu Jinghui said: "There are no murderers who only rob once. When a good man goes to Liangshan, robbing homes and houses has become a daily business."

Jiang Yuan nodded and said, "This shows that the original purpose of the case is probably not robbery."

"Yes, the purpose should not be robbery, let alone murder." Liu Jinghui paused and continued: "Judging from the way of killing, beheading may seem cruel, but it is actually very unprofessional. It also proves the murderer's amateurishness. Sex. However, there is something about the murderer’s method. I think he must have been exposed to similar jobs, such as a butcher or a doctor.”

"If it was a doctor, shouldn't he be killed and then divided?" Jiang Yuanxiao objected.

"It's possible." Liu Jinghui nodded and asked, "What evidence can you see here, and why do you give it a high score?"

"There was only one bloody footprint at the scene. Male, about 38 years old, 175 centimeters tall, with a slight lameness in his left leg." Jiang Yuan emphasized: "The degree of lameness is not too severe. The left leg should be slightly shorter than the right leg, but If you wear height-increasing shoes, you won’t be able to see it.”

Liu Jinghui's eyes lit up when he heard this: "No wonder you gave me a high score. This case should be ranked first. If you have a lame leg, it will be much easier to find someone."

A lame leg is very recognizable. If it is not concealed, people around you will basically notice it when you walk.

This is much easier to distinguish than two arms of different lengths, or two eggs of different sizes, and doesn't even require special attention.

"The DNA is also there, but they didn't find it out back then." Jiang Yuandao: "I'm afraid the two of them are no longer in the area."

"Well... it's very possible. The investigation back then should have been quite detailed." Liu Jinghui felt a little heavy at this time. If the person left or was a foreigner, the investigation would be ineffective.

Without investigation, the criminal police's combat effectiveness will drop by 30%.

"A lame butcher? And with DNA, it is indeed a breakthrough." Liu Jinghui nodded. After all, it is a murder case backlog. It is actually very difficult to have so many clues.

But compared to the first case, there is no way to achieve a direct breakthrough in this case.