"Could this be blood?"
Yang Bairong put on latex gloves, picked up the towel and examined it carefully, even bringing it to his nose to smell it.
Besides the strong smell of glue from the explosion, the faint smell of blood on the towel caught Yang Bairong's attention.
Besides the towel, we've also collected quite a few pieces of wreckage that don't belong to the car.
It was estimated that it was related to the detonation device of the explosives, and Yang Bairong collected and categorized them all.
...
Before leaving get off work in the afternoon, Qin Wen approached Li Nan with the lab results: "Old Li, guess what we found?"
"Could this be a clue to the Blood Rose?"
The 0321 case had just passed, and Li Nan couldn't get the Blood Rose and the mysterious man out of her mind.
"Look at your brain! Here are today's lab results!" Qin Wen pushed the lab results into Li Nan's arms. "We tested the suspicious traces on the towel and confirmed that it was human blood. The DNA sequence in the blood just happens to be in our department's database. Isn't that a coincidence?"
"Whose is it? It couldn't be Peng Yuanyuan's own, could it?"
The An Ding Si (An Ding Si Detention Center) has regulations stipulating that all persons entering the An Ding Si detention cell, regardless of the reason, must have their DNA information entered and archived.
Li Nan's first thought was naturally of Peng Yuanyuan, whom she had just inquired about.
Qin Wen glared at him jealously, "You idiot Li, all you think about is Peng Yuanyuan. Let me put it this way, this is very interesting, it really is related to Peng Yuanyuan!"
"Could it be Zhang Qiqi's?"
"This child is teachable!"
The fact that a towel stained with Zhang Qiqi's blood appeared at the explosion site is such a low-level attempt to frame someone.
Li Nan immediately realized that the towel couldn't possibly belong to Peng Yuanyuan; it was definitely a frame-up!
"Have the composition of the explosive been analyzed?"
"This is easy. A lot of residue was extracted on site, and a simple test showed that it was composed of one part nitrate, two parts sulfur, and three parts charcoal!"
"Homemade explosives?"
"Yes, it's a homemade explosive that any middle school student could make with a little effort. Based on the explosive yield and residual analysis, the gunpowder is estimated to weigh two to three kilograms."
"The purity isn't very high." Li Nan did a simple calculation and knew that the gunpowder wasn't very pure; it seemed to be just homemade explosive.
"But how could explosives of this purity blast such a hole in the back of the truck?"
Qin Wen rolled her eyes at Li Nan as usual, "Don't you know what kind of car Peng Yuanyuan drives? She just drives a KK, okay?"
"Hehe, no wonder, no wonder!"
Li Nan chuckled awkwardly and scratched her head, too embarrassed to ask Qin Wen any more questions, so she started looking through the lab results herself.
Qin Wen did a very detailed job. The test report not only recorded the experimental comparison results of the towel and blood, but also the experimental analysis of the explosives.
They even created a simple reconstruction of the scene based on the videos and photos sent back from the site and the information they collected.
The explosive device was encased in a hard plastic shell that closely resembled the color of the car. Inside were two liters of explosives, a bloodstained towel, and a cleverly designed detonator.
When Li Nan saw the conjecture about the detonation device, his eyes lit up.
"This murderer is a genius! How could he think of such a method?"
After finishing his exclamation, Li Nan looked pitifully at Qin Wen again, "Honey, I don't quite understand this principle, can you explain it to me?"
Qin Wen snatched the test results and slammed them hard on Li Nan's head twice.
"He's utterly ignorant and incompetent!"
The principle of the detonator is simple, but it is actually quite ingenious.
Simply put, it uses the inertia of a car accelerating to accelerate the pendulum striker in the detonator.
This firing pin is different from the usual ones; it's a small ball made into a pendulum shape with spikes, and the ball has four rings around it, all of which are detonation points.
When the car accelerates to its design speed, the ball has enough kinetic energy to hit the detonation point and cause an explosion!
"The murderer who devised this device was clever, and his wife's ability to crack it made her even more clever!"
Li Nan was incredibly adept at flattering Qin Wen, but this time, he missed the mark.
"I dare not claim this credit. It is thanks to Master Cao from the Trace Evidence Department. He has been on the battlefield and is quite familiar with these things. After studying it, he understood the murderer's tricks!"
"Master Cao is amazing!"
Qin Wen continued, "Master Cao also explained that this can be considered a kind of speed bomb. If the car's acceleration does not meet the design requirements, even if the ball hits the detonation point, it will be useless because the force is not enough to trigger an explosion."
"No wonder nothing happened during the dozens of kilometers from Lakeside Moonlight to the toll station, but Peng Yuanyuan exploded as soon as she exited the toll station and entered the highway. It turns out that her acceleration was insufficient!"
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