Chapter 26 Fingerprint Developer
"Xiao Lu, the handlebar is the key point. Whether the other party is pushing an electric bicycle or riding an electric bicycle, the handlebar is the part that the murderer must touch."
The posture of Yang Sen's imitator driving an electric car is analyzed to analyze the places where the murderer may have touched.
“There are no people in the two kilometers surrounding Xingfu Reservoir. It is unlikely that the other party is pushing an electric car...”
Liu Guodong picked up a strong flashlight, shined it on the pedals of the electric car, and observed carefully Are there any footprints left?
If you push an electric scooter, the other person will not be able to touch the pedals, but if you ride an electric scooter, you will definitely leave footprints on the pedals.
Lao Bai was cleaning the hair in the rear wheel bearing: "The body should have been placed across the back seat, so that the hair would be rolled into the bearing."
"Ding!"
"Advanced mission: By surveying electric vehicles, we collected fingerprint information to help the action team locate the suspects and detect the case of corpses buried in Xingfu Reservoir."
Lu Chuan, who accepted the mission, paid attention Observe the position of the armrest in the back seat.
If the murderer wants to push the electric car into the reservoir, his fingers are likely to hit the armrest of the back seat.
While Lu Chuan and others were investigating the electric vehicles, the investigation criminal police of the action team were also rapidly advancing their work.
"Team Qin, we have found out the origin of the electric vehicle."
Ren Qiang took the electric vehicle registration information given by the traffic police: "The owner is Wang Song, and he opened a store of his own. Small restaurant. "
"It was stolen three days ago. The local police sent all the alarm records to Wang Song."
Three days ago, it was the time when the victim was killed.
“Where was the electric car stolen?”
“No. 28, Beihu Road, right in front of Wang Song Restaurant.”
“There is surveillance video "?"
Ren Qiang shook his head: "The car was parked in a blind spot, and there was no sign of the car thief."
"Check, conduct a key investigation on this Wang Song," Qin Yong thought for a moment and began to arrange the next tasks.
Qin Yong has seen a lot of thefts committed by guards.
"Also contact the traffic police. The murderer who stole the electric car and dumped the body will definitely leave video data along the way."
"Confirm all the traffic from Beihu No. 28 to Xingfu Reservoir. Call up all the surveillance on the passing road section, and don’t let anyone go!”
What is the murder mechanism? It is to try your best to invest the most resources and solve the case in the shortest time!
In the detachment courtyard.
Liu Guodong and others looked at the electric car in front of them with gloomy eyes, feeling helpless.
"Old Liu, the electric car has been soaked in water for too long. There is no way to extract fingerprints."
For an afternoon, there was no progress in the current investigation.
On the other hand, Lao Bai has completed the DNA information comparison.
The hair in the rear wheel bearing of the electric vehicle belongs to the deceased.
At this moment, only Lu Chuan was squatting on the ground, scanning every part of the electric car inch by inch.
Liu Guodong thought of the corpse fingerprints extracted by Lu Chuan that morning, which were extremely complete.
There is also the matter of helping Operation 2 Team Ren Qiang and others extract fingerprints at the scene of an arson case in the southern suburbs a few days ago.
Coupled with Lu Chuan's careful and serious look now, he had expectations in his heart.
"Xiao Lu, is there anything you can do?"
Although Lu Chuan was frowning slightly at this moment, his expression was still relatively relaxed.
The intermediate fingerprint collection skills rewarded by the system include many techniques and methods.
Especially to deal with fingerprints caused by fire or blisters, there are special fingerprint collection methods.
Although the electric vehicle involved in the case had been soaked in water for three days, Lu Chuan was still able to collect residual fingerprint information.
"Master, there are some discoveries."
Lu Chuan took out a purple light from the discovery box and shined it on the handlebars, back seat and pedals of the electric vehicle.
"I have carefully observed these places, and there are no traces of wiping."
Liu Guodong nodded: "There are indeed no traces of wiping. There should be fingerprints on them, but after being soaked in water, there are no traces of wiping at all. Unable to extract.”
Liu Guodong has just tried it, and ordinary physical and chemical methods are unable to extract fingerprints. After three days of soaking, the sweat that forms fingerprints has long since dissolved.
Even the water-insoluble part of the grease will be so diluted that it cannot develop fingerprints after being soaked for a long time.
In this field of investigation, the most fearful thing is water cases.
The longer the time, the less things can be discovered.
Lu Chuan nodded: "After soaking, conventional methods cannot extract fingerprints, but some special methods can still have some effect."
Turning off the purple light, Lu Chuan frowned: "There will be some problems in extracting the completeness of the fingerprints."
Oh?
There is a problem with the integrity, but it cannot be extracted?
Liu Guodong raised his eyebrows: "Xiao Lu, do you mean it can still be extracted?"
"Yes, but I have to prepare."
An hour later.
Lu Chuan returned to the courtyard again.
This time, he had a small watering can in his hand.
For this hour, Liu Guodong and the others have been following Lu Chuan.
Witness with your own eyes how Lu Chuan evolved from a criminal policeman to a... chef.
Yes, chef.
This guy has been hanging around the detachment kitchen for the past hour.
Rifled through the bottles and jars inside.
I prepared such a bottle of dark stuff.
"Xiao Lu...can you...do it?"
Lao Bai was a little confused. Although he didn't understand the details of what Lu Chuan did, he knew that Lu Chuan was making his own fingerprint developer.
But, isn’t this thing only done by legendary masters?
Lu Chuan...make your own fingerprint developer?
Liu Guodong's eyes narrowed slightly and he looked at the small watering bottle in Lu Chuan's hand: "Lu Chuan... are you sure?"
Fingerprint developer is available in the criminal investigation detachment and is distributed by the superiors.
In fact, the ingredients are very simple, mainly water and some chemical coagulants.
This fingerprint developer is commonly used nationwide and has a stable structure. It is a commonly used material when extracting fingerprints.
But before uniform distribution, each place had its own commonly used fingerprint developer.
In history, there have been many cases where on-site fingerprints were damaged due to unstable developer.
Therefore, homemade fingerprint developers were no longer allowed to be used.
Lu Chuan's ability to make his own developer shows that Lu Chuan's ability in collecting fingerprints has surpassed that of Liu Guodong and the others.
But on the other hand, if there is a problem with the developer, it destroys the fingerprints on the electric car.
This responsibility belongs to Lu Chuan.
It is normal for an electric car to be soaked in water for three days and fingerprints cannot be collected. No one can blame the people in the current survey office.
The next best thing is to report it to the provincial department and have experts from above come over to investigate.
However, if the developer destroys the fingerprints, the experts coming from above will not be able to collect the fingerprints.
Then this responsibility belongs to Lu Chuan.
This is also the reason why cutting-edge technology is rarely used in the field of criminal investigation.
Stability is the lifeline of the criminal investigation field.
Lu Chuan obviously understood what Liu Guodong meant.
He cares about himself.
As for concealing the use of developer, that is impossible.
Fingerprint developer is a chemical substance and will definitely leave traces after use.
These must be recorded. This is a process issue and no one can violate it.
So, does Lu Chuan want to take the risk?
(End of this chapter)