Chapter 40.1: Counterfeit Coupon
“Jiang Xia, you’re making this sound way too easy.”
Trace Examiner Li shook his head. “According to what you said earlier, this area is basically a complete blank slate. We have to start from scratch and analyze the characteristics. We don’t even know whether we’ll be able to identify any characteristics at all, and you’re already talking about establishing standards. That’s like trying to build a skyscraper before the foundation is even stable!”
After saying this, he set down the lock cylinder he had just removed and sighed before continuing, “In my opinion, let’s not aim so high for now. We should just focus on finding the scratches made by iron hooks. As long as we can distinguish those, it’ll be enough to help narrow down the direction of this case.”
No!
If the department could officially launch this project, Jiang Xia could pick locks hundreds, even thousands of times. Maybe she could even grind her Trace Examination skill all the way up to LV4—the level of a specially appointed expert.
She absolutely couldn’t let such a great opportunity slip away.
Jiang Xia immediately said, “It really isn’t that difficult. Put simply, all we have to do is identify the characteristics, compare them, distinguish their similarities and differences, then summarize the experience we’ve gained and verify it. Once we’ve confirmed that it’s accurate, we’re done.”
“If we’re being honest, the troublesome part is finding the characteristics during the initial stage. We’ll need a large number of sample cases to summarize them, so it’ll take quite a bit of time. It’s just that we can’t get that many locks all at once. But all of these problems can be solved. At worst, we can take it one step at a time. We can start by examining the few dozen locks we already have.”
Trace Examiner Li fell silent.
He had to admit that, sometimes, he really admired this newcomer who hadn’t been in the department for very long.
Whether it was because she was young or not, she genuinely dared to think and act. No matter how big the matter was, she dared to imagine tackling it. And once she broke it down into smaller parts, even something enormous became incredibly simple, as if all she had to do was reach out and she could accomplish it.
It had been the same when she drew the trace diagrams before.
And now it was the same with lock marks.
The batch of trace diagrams that he had previously thought she would never be able to complete had already been finished.
What about the lock marks?
Could she actually pull this off too?
That thought flashed through Trace Examiner Li’s mind, but in the next second, he felt that he was probably overthinking it.
Drawing trace diagrams was just a matter of copying what was already there. This, however, meant identifying characteristics completely from scratch. The difficulty was on an entirely different level, and the chances of success were simply too low.
Still, there was no need to dampen the enthusiasm of a newcomer.
After all, they had to examine these lock cylinders eventually anyway.
“If that’s how you want to put it, then let’s just take a look and see.”
After saying this, Trace Examiner Li paused for a moment before adding, “I’m getting old, and my eyesight isn’t very good either. I may not be able to examine all of them. I’d say you’ll probably have to do most of it.”
Jiang Xia thought so too.
After all, Trace Examiner Li had never been particularly good at identifying and distinguishing minute traces. Otherwise, he wouldn’t have wanted to give up in the first place. Just looking at the marks was already difficult enough for him, let alone the fact that simply looking wasn’t sufficient. They would also need to summarize similarities from a large number of samples.
And they couldn’t just examine the lock cylinders one by one and try to summarize everything from memory. They would have to draw the marks out so they could compare them side by side.
Forget the department—even across the entire city, who could draw them better than her?
Jiang Xia said casually, “Then I’ll do it. As long as you don’t mind me taking your job.”
As she spoke, she glanced up at the section chief, who was deep in thought. After pondering for a moment, she added jokingly:
“Come to think of it, this field is still a blank slate. If we really manage to establish a unified identification standard for traces on lock cylinders, wouldn’t that put our technical expertise at the forefront of the entire country? I feel like we could even submit a paper to Forensic Science and Technology!”
Just as doctors had journals like The Lancet for professionals to submit their work to, criminal investigators had specialized journals of their own. Forensic Science and Technology was one of them.
It was a domestic academic journal that had only been established relatively recently—this year was merely its sixth year—but its standing was exceptionally high. It was supervised by the Ministry of Public Security and published by the Ministry of Public Security’s Institute of Forensic Science. It was a comprehensive academic journal covering forensic science research from both China and abroad, as well as major technological breakthroughs.
It was considered one of the most authoritative and prestigious journals in the field of criminal investigation, and police departments across the country subscribed to it.
If they could publish a technical paper there, it wouldn’t merely be a matter of gaining recognition and fame.
Right on Photographer Zhao’s desk happened to be three copies of Forensic Science and Technology. Hearing Jiang Xia say this, he instinctively glanced at the journals on the desk. The light-blue, high-quality glossy covers left him momentarily speechless.
“That’s a national-level journal! Jiang Xia, you’ve certainly got some nerve dreaming that big!”
“Mm-hmm.”
Jiang Xia folded her arms across her chest and raised her chin slightly, looking completely confident. “I’m just thinking about it. It’s not against the law to dream, so what’s there to be afraid of?”
“And that’s what they mean by youthful ambition.”
Photographer Zhao shook his head. They hadn’t even gotten the first stroke of the character written, yet she was already thinking that big—and was even casually announcing it to everyone. She really was young. Wasn’t she afraid that if it didn’t work out later, people would make fun of her?
Since they weren’t close enough for him to speak too frankly, he didn’t say much more. He merely mocked himself, saying, “An old man like me wouldn’t dare dream like that.”
Jiang Xia smiled and didn’t continue the topic. Instead, she turned her gaze toward Section Chief Liao.
This project was no small undertaking. It would probably occupy a considerable amount of her working hours over a long period of time. And obtaining the locks would be another major problem. She couldn’t be expected to waste her own energy solving that too.
Besides, even if she solved all those problems herself, when the credit was eventually distributed, it would still be counted as a collective achievement. At most, she’d be listed near the top.
In that case, she might as well dangle the prospect of success in front of her superior ahead of time and get him to take responsibility for the logistical support. That would save her the trouble.
Sure enough, the moment Jiang Xia mentioned submitting a paper, Liao Zhongsheng immediately realized that if they really managed to develop this, it would be a tremendous achievement.
After all, this would be a research achievement produced by a department under his leadership—something at the national forefront—and they could even publish a paper about it in a national-level journal.
If they actually got it published, the municipal Public Security Bureau would definitely recognize his achievements this year. Once he had accumulated enough seniority over the next couple of years, being promoted to deputy division-level rank would basically be a sure thing.
And even if they couldn’t get it published there, they could still submit it to the provincial level. The achievement would simply carry a little less weight.
But achievements like this were always hard to come by. Having one was already something to be grateful for!
Liao Zhongsheng was tempted.
Snatching this talent really hadn’t been a mistake.
She certainly knew how to stir things up—but she could really deliver results, too!
“Having dreams is a good thing.”
He looked at Jiang Xia, his eyes full of expectation. “If you really manage to develop this, it would fill part of the existing gap in the field of forensic science and technology, and it would be of tremendous help in solving cases. Xiao Jiang, go ahead and do it without holding back. The department will definitely give you the greatest support we can.”
“Don’t worry, Chief.”
Jiang Xia straightened up as well. “I’ll definitely work hard on the research!”
With this project, she could pick locks to grind system points and improve her abilities, while also publishing a paper, getting promoted, earning a higher salary, and receiving commendations.
One job, two paychecks.
She was practically making a killing!
There was no way she wasn’t going to work her hardest to get this project done.
＊
With Liao Zhongsheng’s approval, Jiang Xia’s lock-picking became much more legitimate.
She picked through two-thirds of the locks Trace Examiner Li had brought over in one go. After grinding out more than forty points, she finally stopped, reluctantly turning her attention to the hellish task that awaited her.
That’s right.
Hell.
Although she’d made it sound simple, observing traces on lock cylinders was actually extremely difficult—enough to make one’s head hurt even more than fingerprints.
There was so much accumulated experience when it came to finding and distinguishing fingerprints. You could simply follow established methods and look for them.
But lock cylinders were a complete blank slate.
What’s more, whether it was a piece of wire or a key, the area in contact with the lock cylinder was extremely small. Because of the limited range of movement, the friction marks they left behind were not only tiny but also incredibly faint. Without light hitting them at the right angle, they couldn’t be seen at all.
Even worse, because there was no existing experience to draw upon, Jiang Xia couldn’t even determine whether a mark revealed by the light at a particular angle was actually a scratch caused by a piece of wire.
All she could do was grit her teeth and draw everything she could see.
The result?
She had to draw more than ten diagrams just to finish documenting a single lock cylinder.
And that was only one lock.
To reach an accurate conclusion, they would need a sufficient number of samples. Statistically speaking, at least three samples were needed to calculate the mean and standard deviation and make an initial assessment of whether the trace characteristics were stable.
But they obviously needed more than that.
Ideally, they would need around ten samples to better eliminate outliers.
In addition, they would need new locks, as well as locks that had been used for three months, six months, one year, two years… For each corresponding period, they would also need to draw and compare the trace patterns left by newly cut keys, wire picking, and at least three other methods of lock picking before they could summarize the relevant patterns and build up a body of experience.
The sheer number of samples they needed was enough to make one’s scalp tingle.
But she’d chosen this path herself, so even if she had to crawl along on her knees, she had to see it through.
After spending five or six days on it, Jiang Xia finally finished the diagrams for one new lock, one old lock that had been used for two years without ever having another key cut for it, and the trace patterns from an old lock that had likewise been used for about two years without a new key being made—and that she had also picked herself.
The moment she finished, Jiang Xia leaned back in her chair and completely collapsed into a pancake.
It felt like she’d been transported back to the days of intensive training for the joint entrance examination.
It was absolutely terrifying.
“You finished the old lock too?”
Seeing Jiang Xia stop, Trace Examiner Li got up and walked over to her desk.
The microscope he’d previously used with great care now sat quietly in front of Jiang Xia.
At first, Trace Examiner Li had wanted to try using the microscope himself to look for traces and draw some diagrams by hand.
But one afternoon, after his eyes had grown tired from examining the marks, he let Jiang Xia take over the equipment and draw them.
And, well…
Not only were her drawings exactly identical to what he saw through the microscope, but when he placed his own drawings beside hers for comparison, his looked like a child’s scribbles. There were also many tiny traces he’d failed to notice that Jiang Xia had spotted and drawn.
Trace Examiner Li didn’t know whether they would actually succeed in developing a method for distinguishing lock traces, but when it came to Jiang Xia’s eyesight and drawing skills, he was genuinely impressed beyond words.
So Trace Examiner Li simply handed the entire burden of examining the traces and drawing the diagrams over to Jiang Xia.
There was nothing he could do.
Who could blame him? He couldn’t examine them as thoroughly as she could, and he certainly couldn’t draw them as well.
Reluctantly, Trace Examiner Li finally pulled his gaze away from the microscope and reached out to pick up one of the diagrams.
Seeing this, Jiang Xia, still sprawled limply in her chair, quickly warned him, “Careful, Teacher Li. Don’t let your hand touch the drawing. I haven’t applied the fixative yet. You’ll smudge it.”
Trace Examiner Li nodded repeatedly. “Oh, okay. I definitely won’t touch it.”
The drawings were anything but easy to make. If he accidentally dirtied one, Jiang Xia might not say anything, but he’d want to punch himself in the face.
Carefully holding the drawing by its edge, Trace Examiner Li pushed up his glasses and studied the traces on the page.
He had to admit, there was something satisfying about looking at drawings that were identical to the actual traces, only magnified several times over.
He picked up the three sets of lock-trace diagrams and compared them for quite a while before finally speaking.
“There really are quite a lot of traces here. We have both static three-dimensional traces and dynamic three-dimensional traces. They’re really difficult to distinguish.”
It took Jiang Xia a second to realize what Trace Examiner Li was talking about.
That was a theory from twenty or thirty years ago.
At the time, China’s criminal investigation field primarily followed Soviet theoretical methods, dividing tool marks into two categories.
One was three-dimensional marks produced by impact or pressure, while dynamic marks were produced by friction.
This classification was far too broad, and it often felt rather vague when applied in practice. So over the past decade, further classifications had been developed. Based on the characteristics of tool marks, they were divided into six categories, including prying/pressing, impact, and rubbing/scraping.
The latter classification was more commonly used nowadays, but old-school trace examiners like Trace Examiner Li were still more accustomed to using the former terminology.
“I think they’re actually pretty distinguishable.”
With the new lock as a comparison, the traces that had originally been difficult to distinguish now became much clearer.
Jiang Xia said, “Objects can only leave corresponding traces when force is exerted between them. If we analyze them from that perspective, things become much easier.”
“For example, when a key opens a lock, the key first enters completely and engages with the pins, and then it’s turned. Based on the interaction of forces, these several straight, radially distributed marks on the rounded surfaces of the pins look very much like rubbing and scraping marks left behind by a key. What’s more, the traces across the entire surface of the pins gradually become smoother from front to back, tending toward a polished state. That also fits the characteristics of a lock that has been opened with a key over a long period of time.”
“And then there’s this lock that was opened with an iron hook. To open the lock, the hook has to pass across the individual pins and push them upward. I found several extremely fine longitudinal scratches on the inner walls of the pinholes. They look very much like marks left by the iron hook scraping across them.”
“And there are also two small, point-like pressure marks on the pin connected to the lock-opening mechanism.”
Trace Examiner Li was utterly stunned.
Wait. She just finished drawing these. He was still comparing them and trying to figure out what was different, and she’d already started identifying patterns?
Wasn’t she moving way too fast?
And she even sounded like she knew exactly what she was talking about…
Trace Examiner Li pushed his slipping glasses back up again. Still holding the diagrams, he continued comparing them and asked, completely unconvinced, “This is only one set of diagrams. How can you be so certain that these are key marks and scratches made by an iron hook?”
“Because of mechanics.”
Although Jiang Xia had been an art student in her previous life, she’d studied the sciences. She hadn’t been bad at either mathematics or physics. Unfortunately, she’d majored in architectural design at university—a field that had already become something of a notorious dead end.
Just thinking about it brought tears to her eyes.
Who would have thought that the physics she’d studied back then would not only come in handy again now, but that she’d even get the chance to delve into it more deeply?
Straightening her back, Jiang Xia picked up the lock cylinder and iron hook, demonstrating with them as she spoke.
“Trace Examiner Li, look. A trace is something left behind when one object exerts force on another. So analyzing it according to how forces act can’t possibly be wrong. For example, there’s action and reaction, as well as the nature of the contact between objects. It’s just like this…”
As everyone knew, mathematics and physics—the two great academic power couples—had never let ordinary mortals down. And mechanics, one of the four fundamental pillars of physics, sounded even more soothing than a lullaby.
Trace Examiner Li had originally intended to follow along carefully and learn something.
At first, he could still remember what she was saying.
But as he listened and listened, his eyes gradually went blank. The light in them slowly disappeared, and even his upper and lower eyelids began fighting each other.
“I’d better get you a glass of water.”
After suddenly jerking awake when he lowered his head, Trace Examiner Li proactively put down the diagrams he’d been holding. He poured her a glass of water and said with particular thoughtfulness, “One set of diagrams definitely isn’t enough. Anyway, Jiang Xia, get some rest. I’ll go find Section Chief Liao and get everyone to help collect more samples.”
With that, Trace Examiner Li hurriedly turned around and left the room.
The rest of what Jiang Xia wanted to say remained trapped in her stomach.
I hadn’t even finished explaining the magnitude of the force yet! Trace Examiner Li, why are you in such a hurry to leave?!
She had only just gotten interested!
Jiang Xia looked around the room, still feeling unsatisfied.
Forensic Doctor Sun and Yang Lihua were still happily swimming in the ocean of medicine. Photographer Zhao was still holding a newspaper, his attention nowhere near her. Huang Xueling, meanwhile, had her chin propped up in her hand, apparently trying to listen in, but her eyes weren’t really focused on the conversation either. She had probably already started thinking about what to eat for lunch.
When Huang Xueling noticed Jiang Xia looking her way, a sudden chill ran down her back. Instinctively, she withdrew her hand and lowered her head, immediately focusing on the fingerprints in front of her. She looked as serious as could be.
Jiang Xia could only regretfully look away and flop back into her chair, going back to playing dead.
Huang Xueling gradually let out a sigh of relief.
That was close, that was really close.
She’d almost gotten dragged over to attend another lecture.
Compared with all those forces that made her eyes swim and ears ring just thinking about them, fingerprints looked much more familiar and approachable.
That blessing of having to sit through lectures can stay with Master. I don’t want it!
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