novice forensic medicine

Chapter 10 The Hidden Bloodstain

Xu Dayuan went to investigate the investigators, Zhou Ning and the others quickly checked the two cars.

Touching the Volkswagen CC, Zhou Ning thought in his heart and submitted a temporary task: This is the vehicle that caused the accident.

After waiting for a while, the system did not respond at all.

It's not like the first time the task was submitted, it just popped up and said that the task was submitted successfully, and the reward was drawn. What is the reason for this, and I answered wrong?
This idea was directly overthrown by Zhou Ning. If he was wrong, according to the urine nature of this system, he jumped out and downgraded the previous rewards.

Thinking about it carefully, this temporary task seems to have two requirements.

That was to find the vehicle that caused the accident and the perpetrator who injured the deceased. It seemed hasty. He didn't even think about submitting the first task, but the idea popped up in his mind, and the task was over.

Zhou Ning's eyes flashed, which means that the current answer is not wrong, but not enough standard, or his answer is correct, but not comprehensive enough, and lacks evidence.

Didi thought twice, and a task submission page popped up on the transparent display screen, with three conditions on it.

evidence?

driver?
The vehicle involved?

Zhou Ning made a wrong tooth, I went there and it was true, you are a trap, if I didn't analyze it myself, this task would not be able to be submitted, after all, the submission page has not been opened.

With a sigh, Zhou Ning looked at the criminal police who were circling around the car. Zhao Xinli had already taken down the investigation box and distributed the things.

There is no technical content in collecting fingerprints, but carefulness. Zhou Ning was not in a hurry to get into the car. The door handles, windows, upper edge of the door, and central control switch, wherever the door can be opened and closed, Zhou Ning carefully wiped them with a brush dipped in special powder. Pass.

Several fingerprints appeared, and Zhou Ning extracted them carefully.

"Forensic doctor Xiao Zhou, I also found a few fingerprints here."

Zhao Xinli was kneeling on the co-pilot of the Nissan, with an isolation suit under his knees. Sure enough, there were fingerprints and palm prints on the shift handle.

Zhou Ning extracted it carefully, held up the collected items, and looked at the Volkswagen CC on the side. The three people in that car were searching. Why is there no movement at this moment?

Throwing things to Zhao Xinli, Zhou Ning walked towards Volkswagen CC.

"Have you found nothing here?"

"I only found the fingerprints of a few lint gloves, and found nothing else. It seems that this car has been cleaned carefully, and the interior has been cleaned after the smell."

Zhou Ning was a little dumbfounded. The car has been repaired and the interior has been cleaned so thoroughly. How can it be proved that this car is the vehicle that caused the accident?
Pushing the door and getting off the car, Zhou Ning stood in front of the car and looked at the car carefully.

"Brother Zhao, in 24 hours, do you think it is possible to repair a car that has been in an accident to such a brand new state?"

Zhao Xinli shook his head decisively.

"No."

"cannot?"

Zhou Ning was taken aback, Zhao Xinli quickly opened the engine cover, pointed inside and said.

"Don't worry, if you want to paint the sheet metal, you can't finish it. I looked inside and found that the engine cover and the screws in these places have not been twisted, which means that these have not been replaced. The deceased did not have a broken calf. That is to say, the speed of the car hit the leg of the deceased, and the person was directly thrown out.

If this is the case, the damage to the car is not serious, just replace the bumper and headlights, and there will be no traces. Of course, if we replace it with the same car, we will not be able to see it. As for the tires, I think they have been replaced. "

Zhou Ning pushed his glasses, and the image that the deceased found at the first scene appeared on the transparent display screen and was still rotating. Zhou Ning stared at the glass shards on the deceased's cheek and shook his head slowly.

"No, the deceased not only had a fractured tibia and fibula in her left leg, but also had glass shards on her left face and bruises around her eyes, which means that after being hit on her leg, her head hit the glass from the side."

When Zhao Xinli heard it, he lay down on the corner of the windshield from the side, held up a magnifying glass and looked there for a long time, his eyes lit up instantly.

"Excellent forensic doctor Xiao Zhou, this windshield has indeed been replaced. Although this is the original glass, the production date is wrong!"

This discovery made Zhou Ning silent.

The windshield, bumper and headlights have been replaced. If the replaced items are destroyed and the suspect refuses to admit it, then the car cannot be identified as the vehicle that caused the accident. It can only prove that the two participated in illegal racing. What's missing.

Zhou Ning stood in front of the car and didn't speak for a few minutes. A few criminal policemen seemed to want to say something, but Zhao Xinli stopped him. He had figured out the temper of this little Zhou forensic doctor. good idea.

Zhou Ning, who was in deep thought, thought of the injury in the ribs of the deceased and the on-site sampling content learned last night, and suddenly his eyes lit up.

Zhou Ning moved, found a bottle of luminol reagent [1], and quickly sprayed it evenly on the hood. In the middle of the hood, two columns and a huge blue-green fluorescence appeared.

This discovery made Zhou Ning more confident. He leaned on the edge of the windshield from the side of the front of the car and sprayed the luminol reagent in the gap where the windshield and the hood meet. Sure enough, there was also a fluorescent reaction here.

On the wiper cover, Zhou Ning found two purple-black blood drops and waved towards Zhao Xinli.

"Pass me the camera, and give me the swab for sampling [2]."

Zhao Xinli quickly handed over the camera, then found the test tube and swab, leaned close to Zhou Ning, watched him take pictures, and asked enthusiastically.

"What did Xiao Zhou's forensic doctor find?"

"Blood, I suspect it's the blood of the deceased, fell on the wiper cover, probably not found during cleaning, just wiped off the blood on the hood.

Although it is impossible to sample here, the shape of these two columns is exactly the same as the blood stain on the lower edge of the rib on the right side of the deceased. The county hospital can do it. "

Zhou Ning spoke quickly and his hands moved even faster. The swab was dipped in distilled water to collect a blood sample, and one end was broken off and thrown into the test tube, and handed to Zhao Xinli.

Zhao Xinli didn't talk nonsense, grabbed the bottle and ran away. Zhou Ning climbed out of the car, took the fingerprints and palm prints just collected, went up to the second floor and went straight to the office.

Turn on the computer with the big belly display. Regardless of the shabby computer, the performance is not bad, and there is also a fingerprint comparison software installed in it.

Zhou Ning entered the fingerprints and palmprints he had just collected into numbers respectively, and did the same with the fingerprints marked with Yang Feiyu and Wang Fuhao on the table, and then clicked to compare.

Except for a few that are too incomplete to be compared, several fingerprints show that the comparison is successful, and you can directly click to print the comparison result.

Zhou Ning clenched his fist and waved it. Great, although there is no fingerprint in the Volkswagen CC, Wang Fuhao's fingerprint was found on the door and gear handle of the Nissan car.

As for who hit the deceased, the result is self-evident, but why did Wang Fuhao rush to repair the car and help Chen Yufei cover up the evidence?
As Zhou Ning's thoughts popped up, the familiar prompt sound came from Zhou Ning's ear.

Congratulations to the binding person, the temporary task has been successfully submitted!

Evidence: Fingerprint collection completed, bloodstain extraction and comparison successful;
Driver: Yang Yufei;
Accident vehicle: Volkswagen 2010CC
Countdown time remaining: 33:30
Rewards are being distributed, and the loading time is 10 minutes.

Zhou Ning sat down subconsciously. After all, the discomfort during the loading process last time left him with lingering fears. Fortunately, he was in his office this time. Sure enough, the feeling of head-swelling came again, but the degree was not as uncomfortable as the first time.

This feeling lasted for a long time, Zhou Ning even felt that time seemed to slow down, and with the two beeps, all the discomfort dissipated.

Zhou Ning sat slumped on the chair, gasping for breath, curiously flipping through the knowledge he learned on the spot in forensic medicine in his mind, but couldn't find any results from other comparisons, so he directly turned to the end of the part on rubber trace inspection, and found the following paper.

Sure enough, the last paper is in 2019, [year (volume) issue] 2019 (036) 008, Zhou Ning is gearing up excitedly.

Awesome, this is another three years of new knowledge.

Picking up the comparison result, before he got up, the door of the office was pushed open. Xu Dayuan strode in. Seeing the expression on Zhou Ning's face, he asked hopefully.

"How is it? What evidence did you find?"

PS:
【1】Luminol: (Luminol) is also known as luminol.The chemical name is 3-amino-phthalohydrazide.It is a pale yellow powder at room temperature, and it is a relatively stable synthetic organic compound.

For the blood that cannot be observed by the naked eye at the crime scene, the luminol reagent can show a very small amount of blood stains (occult blood reaction). At the same time, luminol is a strong weak acid, which has certain irritating effects on the eyes, skin and respiratory tract .

Since hemoglobin contains iron, iron can catalyze the decomposition of hydrogen peroxide, turning hydrogen peroxide into water and monooxygen, and monooxygen re-oxidizes luminol to make it glow.Therefore, luminol is widely used in criminal investigation, bioengineering, chemical tracer and other fields.

Forensically, the luminol reaction can identify bloodstains that have been scrubbed long ago.In biology, luminol is used to detect the presence of copper, iron and cyanide in cells.

[2] Swab: It can be understood as an extended version of the cotton swab, the head can be broken, and it is usually used as a tool for medical examination to collect microorganisms, exfoliated cells or secretions.

(End of this chapter)