Chapter 8 Matching Fingerprints
The old desktop computer creaked and creaked. Google search reading
Whirring hot air blew out of the chassis and dispersed in the air.
After a while, the 20 fingerprints with the highest matching values were displayed on the right side of the LCD screen.
Jiang Yuan was not in a hurry. He took a sip of tea and clicked on the first fingerprint to read.
In the past two days, the criminal police team, which was operating at full capacity due to Uncle Seventeen's murder case, suddenly relaxed, and Jiang Yuan returned to his daily routine as a forensic doctor - without any work.
At the same time, he gradually became proficient in the use of the system reward he had just received, the "Chongqing-style single-finger fingerprint analysis method - bow pattern identification (lv3)".
After doing some exercises using exercise books from his school days and public information, Jiang Yuan decided to enter into actual combat: first find a bow pattern, and then find out who it belongs to.
As the first step, Jiang Yuan chose the fingerprints collected in a robbery case in Longli County, a neighboring city.
The reason why fingerprints from murder cases are not selected is because under the guidance of "murder cases must be solved", murder cases are taken very seriously and there are a lot of resources. Before becoming a backlog of cases, the fingerprints have been compared many times. Fingerprints from the backlog of murder cases that still remain in the fingerprint database must be extremely difficult to identify.
If there is an unsolved murder case in Longli County, and the suspect's fingerprints are extracted, the fingerprints will first be compared by the trace inspection personnel of Longli County multiple times. If the comparison fails, they will have to go to the police multiple times. If all attempts are unsuccessful, the municipal criminal science and technology squadron will be asked for help, or the provincial department may be contacted directly.
If the fingerprint still fails to match at the provincial and department level and the case remains unsolved, then every one or two years or so, the provincial department and even ministries will organize special fingerprint battles to analyze the fingerprints involved in major backlog cases. In comparison, its participants are often experts from the criminal technical talent pool or youth talent pool of provincial departments or ministries.
Jiang Yuan has already eaten LV3 egg fried rice, so his expectations for the LV3 bow pattern identification are not that strong.
The egg fried rice was delicious, but it didn't shine yet.
It can be deduced from this that LV3's bow pattern identification is very powerful, but it is not superb.
Not to mention, the fingerprint database that he can compare with is now limited. Jiang Yuan feels that it is too easy to be frustrated if he challenges the murder case with the first fingerprint.
In contrast, the heists are more suited to the moment.
On the one hand, ordinary robbery cases cannot reach the level of major provincial cases. On the other hand, robbery cases are taken seriously enough by the county bureau. This determines that when the fingerprint inspection police conduct fingerprint extraction, they must also be Serious enough. The fingerprints finally uploaded to the database are highly relevant to the case.
Having said that, Jiang Yuan was quite surprised when he clicked on the fingerprint image of the case for the first time.
The fingerprints were extracted under unknown circumstances. Not to mention they were blurry and incomplete, only about half of the normal fingerprints. Fortunately, more of the fingertips are preserved, so there is a basis for comparison.
In addition, it goes without saying that fingerprints are deformed.
This situation is completely different from the fingerprints left by ordinary people punching in to work. Without any professional skills, let alone marking feature points, it would be difficult to determine which finger it belongs to.
Unsurprisingly, none of the 20 fingerprints automatically matched by the system were matched.
Jiang Yuan was not discouraged. This kind of fingerprint was uploaded to the system because it was difficult to match in local trace inspection. As for the local failure to match, it may be due to technical problems, or it may be that the corresponding fingerprints are not collected in the fingerprint database.
If it was the latter, then Jiang Yuan had no choice but to hope that the bureau's fingerprint database would be wider... and what he was fighting for now was the former.
For fingerprint inspection police officers who do fingerprint matching, hard work is a must. Only if you work hard can you have a chance to fight for luck.
Jiang Yuan closed the fingerprint comparison page and reopened the suspect's fingerprint image, this time using Photoshop.
He carefully observed the state of the incomplete fingerprints, and then began to adjust the contrast and brightness.
Jiang Yuan's adjustments were so detailed that it took him half an hour to slightly improve the clarity of the fingerprint image.
However, sharpening the knife never wastes time chopping wood. After Jiang Yuan waited for everything to be prepared, and then looked at the fingerprint map carefully, the direction of the lines could be seen more clearly.
Immediately afterwards, Jiang Yuan slightly adjusted the center point of the fingerprint.
Because the fingerprints were so incomplete, the center point itself was uncertain. If Jiang Yuan didn't make adjustments, the system would automatically estimate a center point.
Jiang Yuan watched the direction of the lines, repositioned the center point, then put the software back, changed the conditions, and pressed OK again.
Another 20 fingerprints failed to match.
Then fine-tune the center point and compare again...
This time, Jiang Yuan spotted the third-ranked fingerprint at a glance.
When ordinary people look at fingerprints, they probably think they are similar at first glance. Especially if they are both bow-shaped or bucket-shaped, it is often difficult to distinguish them.
But for people who have been looking at fingerprints, the different fingerprint features are like the freckles on an old sow's face. They feel familiar after looking at them for a long time.
Jiang Yuan directly clicked on the third fingerprint, enlarged it and placed it on the right side of the computer screen, then opened the original fingerprint and placed it on the left side of the screen.
Put the two fingerprints together, and the similarities are immediately apparent.
At this time, we don’t just look at the feature points, but directly judge by the similarity of the fingerprints. In one-on-one situations, the human eye's discerning ability is much better than that of a computer.
"Win the match!" Jiang Yuan muttered to himself, feeling relaxed for a while, and then submitted the matching fingerprints.
According to the rules, the fingerprints he submitted will be submitted to the experts from the provincial department. After the latter reviews and confirms that they are correct, and then clicks submit, someone will notify the corresponding front-line unit, and the local area will arrange the arrest.
Of course, it would be no problem for the local criminal police team to arrest someone.
Jiang Yuan couldn't care about that much anymore. He stretched, stood up and stretched his muscles. He looked at the time again and waited with peace of mind to get off work.
Forensic life without corpses is simple and pure.