Chapter 305 Regression Equation
Captain Ma went out to investigate, and the few people who stayed in the small bathroom calmed down for a while, and each lowered his head and started doing his work.
Jiang Yuan also lowered his head and thought.
For him, the prologue of the case has basically been completed. There are indeed differences in the judgment of the deceased's time of death, but this is not a problem. Maybe, it can be used to solve the case.
Of course, based on Jiang Yuan's experience, even if this skill is not used, there may be other clues to solve a case of this level as Captain Ma returns from the investigation.
Jiang Yuan thinks to reset his thoughts.
Comrade Ye Tianhe was a little noisy.
As a forensic doctor, Jiang Yuan can now understand that Ye Tianhe actually outputs too much directly and is a little unaccustomed to being questioned.
The status of forensic doctors at crime scenes is actually relatively high, and this refers to their professional status.
Generally speaking, after a forensic doctor gives an inference on the time of death at the scene, no criminal police officer will ask: Did you make a wrong calculation?
Even the criminal police captains do not have the relevant professional ability and confidence to make such a judgment. The most they can do is bully the new forensic doctor.
For outsiders, as long as the forensic examiner stands firm and motionless in the face of the corpse and the stench, that is almost enough. The most they ask about is love and family life.
Professional exchanges between forensic doctors are often not too intense.
Especially for grassroots forensic doctors, if you have the support of forensic doctors from higher-level units and recognize your expertise, then you have the final say.
Or, the grassroots forensic doctors themselves are not very professional, their self-confidence is not strong, and they will not get into fierce debates.
Ye Tianhe is actually a relatively strong forensic doctor.
As a forensic doctor of the provincial capital city's criminal police detachment, although Ye Tianhe seemed easy to talk to, he would not fully recognize the technical guidance of the provincial department's forensic doctor.
Therefore, most of the time, Ye Tianhe's output is actually one-way, and there is little verification.
In a normal case, Ye Tianhe arrived at the scene as a forensic doctor. After examining the body and drawing conclusions, the criminal police would not question him. Even if his colleagues were confident enough, they would not be much more powerful than Ye Tianhe. The methods used should be similar, and so should the answers obtained.
As for the truth of the case, we will neither get immediate feedback nor necessarily accurate feedback. In the end, even if the conclusion is that the forensic doctor made an omission, it is a few hours or even a few days, the forensic doctors are actually very relieved. my own.
In fact, when using rectal temperature or liver temperature alone to identify the time of death, the accuracy of most regression equations at the beginning of the design is only 85% or 90%, with an error of one or two hours. In practice, It's a commonplace meal.
Therefore, rather than saying that Jiang Yuan and Ye Tianhe have a conflict of opinions, it is better to say that the standards of the two are not at the same level.
It's been a while since Ye Tianhe encountered such a direct face-to-face challenge.
After calming down, Ye Tianhe soon figured it out and took the initiative to smile with Jiang Yuan: "Jiang Yuan, did you get me into trouble just now? Let me talk to you about the temperature of the corpse, and judge the corpse through the rectal temperature. At the time of death, you have rigor mortis and your corneas are hanging upward." Jiang Yuan looked at the situation and calmed the atmosphere and said: "I came here anxious, anxious and furious. Indeed, other factors, make The death time is different from the death time created by corpse temperature, so the factor of corpse temperature seems a bit abrupt." Ye Tianhe just nodded, with a general understanding.
After all, when forensic doctors determine the time of death, those who can use corpse temperature must use corpse temperature.
Because corpse temperature is easier to quantify. Whether it is rectal temperature, liver temperature, or body surface temperature, etc., putting a thermometer on it will give an accurate temperature.
The accurate temperature is substituted into the regression equation. Even the simplified regression equation gives a conclusion on the time of death that is actually very accurate.
For the criminal police who use this data, whether they are the criminal police of the Changyang City Criminal Police Detachment or the criminal police of the Ningtai County Criminal Police Brigade,
We are very satisfied if the body of the day is accurate to within two or three hours, and the body of a few days is accurate to morning, noon and evening.
The time given by Jiang Yuan was too accurate and was actually beyond the norm.
Ye Tianhe couldn't understand it, which was normal.
Jiang Yuan did not have time to teach him, so he only said: "In fact, if conditions permit, we should be able to draw a relatively accurate conclusion by doing a chemical analysis of the eyeballs. Because the rupture of red blood cells and the accumulation of potassium ions are basically not affected by temperature. Affected." Ye Tianhe said: "Maybe, the main reason is that the time difference is relatively large." "I agree." Jiang Yuandao: "Normal weather, normal environment, such a big time difference is also abnormal."
"kindness."
"I think this is probably because the suspect faked the scene."
Ye Tianhe was stunned, his eyes first fell on the bathtub next to the bathroom, and asked: "How did you forge it?"
Based on his forensic experience, the first thing he thought of was actually through the bathtub.
The effect of water bath on temperature is very large, several times greater than that of air. Therefore, the identification of the time of death of a corpse in the water is very different from the identification of a corpse on land.
If the water is added with ice or heated, the difference can indeed be very large.
Ye Tianhe stepped forward to check the body again, then shook his head and said, "There is no sign of contact with water."
"In fact, you can do the math backwards and use the multiple regression equation."
Jiang Yuan took out the notebook he carried with him and wrote while writing: "Assume that the rectal temperature is Y, the ambient temperature, clothing or coverings, the carrier of the corpse, the ventilation conditions of the environment, humidity, gender, age, body shape, and the cause of death are respectively Adefgh, given the coefficients, the equation is, Y=352-311A+188B+035C+136D+563E+664F+04
Ye Tianhe was a little concerned just now. Jiang Yuan didn't take the rectal temperature, didn't give the data, and just said a number.
Now, listening to the numerical data given by Jiang Yuan, he fell into confusion again.
Jiang Yuan entered the numerical calculation and continued to introduce: "The most important thing here is to quantify Adefgh. For example, the cause of death can be simply quantified according to the amount of bleeding. For heavy bleeding, 2 can be given. If so, the husband has alibi." of. "What kind of evidence." "Jiang Yuan still has to ask. The alibi can theoretically be forged, especially by those who like to engage in perfect murders. There are many discussions about air-to-air, and if it is not guaranteed, some people will discuss it.
Captain Ma shook his head and said: "The evidence is very strong. This husband works in an outsourcing Internet company. There are cameras at the workstation, there are cameras when opening the record, there are also cameras entering and exiting the office building, and there are cameras even after leaving the seat for a long time. There are mobile phone warnings, unless the company commits large-scale fraud, it is impossible.”
"Then there is someone else." Jiang Yuan nodded.
Captain Ma hesitated for a moment and said in a low voice: "Maybe the time of death should not be so tight." "I have checked it and there is no big problem with the time of death." Jiang Yuan shook his head.
"Check the calculation?" Captain Ma asked one more question.
Jiang Yuan tore out the calculation page from his notebook and handed it to Captain Ma.
Captain Ma saw the massive letters and numbers, and then smiled like a pure human: "I don't need to ask anymore."
"This multiple regression equation is not easy to calculate, but someone must have forged the crime scene, and interfered with it and caused the temperature of the body to become disordered." Jiang Yuan did the calculation just to clarify his ideas.
Now that his thoughts were clear, he no longer needed to look at the numbers and said to himself: "Either the deceased was drugged and this requires a toxicology test, or someone made changes to the body or the environment around the body. . This family’s bathroom is not big. If the temperature and humidity are raised for two or three hours and raised high enough, it is still possible. However. "
Jiang Yuan looked at Forensic Ye and Team Ma and said, "If it's high temperature and humidity, you should be able to feel it when you come in."
Ye Tianhe shook his head slightly: "I just walked on the road for 40 minutes.
The police officer who responded to the call didn’t say anything. Can Team MA ask? "
Captain Ma said "Yes" and immediately took out his cell phone to ask.
Soon, Captain Ma put down his cell phone and shook his head: "The two people who responded to the police didn't feel anything."
"Then...ask your husband?" Jiang Yuan hesitated a little.
Captain Ma frowned slightly: "Well...if we are not very sure, I think we can put it back a little bit? Well...assuming that someone really faked the scene and created high temperature and humidity, then there is no high temperature and humidity now, which means that After all, he got rid of the high temperature and humidity in advance. Could it be that he is an old criminal? He sneaked in in advance, committed the crime, and then left."
He was purely cooperating with Jiang Yuan. From the perspective of the Ma Brigade, such complex cases rarely happened. The more old the criminal, the less likely he would make the case like this.
"If you come in, there may be traces." Jiang Yuan simply stood up and said, "Let me help you get rid of it. Forensic Doctor Ye, will you take the body back for autopsy?"
"OK."
Several people stopped talking and went back to the bathroom to start operations.
Jiang Yuan changed his clothes, gloves, put on special eyes, and began to try to investigate the scene from the bathroom.
Everything seemed to be on track.
Just like before.
Captain Ma and Wan Baoming let out a sigh of relief, then looked at each other and smiled.
Just when the two felt relaxed, Jiang Yuan's voice came again: "This family seems to be using a smart home. The air conditioner, bathroom heater and ventilation in the bathroom can all be operated remotely."
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