The afternoon sun at three o'clock was warm but not scorching.
Combined with the gentle breeze blowing in from the window, it was very comfortable.
Chaoyang Investigation Bureau, outside the forensic room.
Guan Guandu and Zheng Yuanqiao were both anxious and impatient.
They have been waiting here for eight or nine hours since morning.
Although I know that forensic identification is time-consuming.
Moreover, what Shen Ting did was not just ordinary physical evidence identification.
More high-end, more refined.
But Guan Guandu and Zheng Yuanqiao still couldn't help but get anxious.
Especially!
During this period, there has been no new progress in the case investigation.
Zheng Yuanqiao's men investigated the auto repair shop but found nothing.
The same applies to Guan Guandu.
Seeing Shen Ting finally emerge from the appraisal room, the two hurriedly went to greet him:
"Shen Ting, how is he?"
"Team Leader Shen, what are the results of the analysis?"
Shen Ting handed the appraisal report to the two men and smiled:
"We were lucky; we did make some unexpected discoveries."
We previously made our judgment based on Wu Liqun's wrench wound and the oil stains found on the fibers under Zhao Huimei's fingernails.
The two perpetrators may have worked in mechanical repair.
That conclusion is correct!
Shen Ting then looked at Zheng Yuanqiao:
"Captain Zheng, didn't you say before that the most common place to get oily smells is auto repair shops?"
This guess might not be wrong.
I have examined more than ten microparticle samples and can basically confirm that these microparticles did indeed come from the car.
Moreover, they are all high-end cars.
For example, the first microparticle I identified was on a copper alloy substrate that had undergone molybdenum-based sputtering.
The molybdenum, tungsten, and carbon elements exhibit specific crystalline forms and proportions.
By analyzing the proportions of different elements, I determined that these metallic particles came from the gearbox of a Porsche 911.
The third metal particle I identified was aerospace-grade aluminum alloy debris.
The copper, magnesium, silicon, and zinc content is the same as that of the aluminum alloy body of the Rolls-Royce Phantom.
I identified the fourth metallic particle as fragments of neodymium iron boron magnets, which came from the tram...
In addition to metal particles, I also found other non-metallic particles that are used in high-end cars.
For example, filamentous carbon fibers, ceramic heat-insulating coating debris...
Zheng Yuanqiao and Guan Du listened to Shen Ting's account while simultaneously reviewing an appraisal report.
They originally hoped to find special clues from it.
You can view metallographic images taken by instruments such as metallographic microscopes and scanning electron microscopes.
The two became increasingly confused as they looked.
They felt like they were looking at a mosaic.
The two simply put the identification report aside.
Zheng Yuanqiao asked curiously:
"These particles all come from high-end cars."
Shen Ting, do you mean that the auto repair shop where the suspect worked was a shop that specialized in repairing high-end cars?
This does indeed significantly narrow down the scope.
Shen Ting first nodded, then shook his head:
"This can only be described as a possibility."
Another possibility is that the two suspects didn't work at the auto repair shop, but rather at a luxury car modification shop.
Modification?
Both the police officers and the forensic experts were somewhat surprised.
Guan Du quickly asked:
"Team Leader Shen, how did you arrive at this conclusion?"
"It's very simple!"
Because of the structure of the metal fragments.
Shen Ting explained:
"The metal debris formed by the wear and tear of a car's structure is usually in the form of micron-sized spheres and ellipsoids."
Furthermore, the surface coating usually wears down significantly, and is replaced by an oxide layer.
The metal fragments in this case also included this type, but they only constituted a very small portion.
The vast majority are angular, exhibiting sharp curls, needles, flakes, or spirals.
There are also small amounts of diamond and silicon carbide particles from the cutting tool on the surface.
These are all typical "cutting chips".
and!
The cross-section of the microparticles has no oxide layer, and the surface coating is relatively intact.
Based on this information, I believe the source of the particles is more likely to be a luxury car modification shop.
"I see!"
Director Ma's eyes lit up:
"Luxury car modification shops are even rarer than luxury car repair shops."
The scope of the investigation has been narrowed further, hasn't it?
Furthermore, the metal particles can be traced back to the Porsche 911 and Rolls-Royce Phantom.
This must be a car modification shop; the car was recently modified.
Based solely on these two luxury car models, it's possible to pinpoint which modification shop it is.
Once the location of the modification shop is determined, finding the two suspects will not be far off.
I have a feeling this case is about to be solved!
...
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