Chapter 27: Extracting Fingerprints and Footprints

"Master, this developer is extremely stable. It was a secret technique from an old professor of mine back in university, specifically used for developing water-soaked fingerprints."

Lu Chuan had no way to explain the origin of his skill, so he decided to attribute the fingerprint developer to an old professor.

"But this developer has a drawback: the development time is short, only about ten seconds."

"Therefore, we need to record the entire process on video, and every single fingerprint must be photographed within ten seconds!"

Lu Chuan's words were forceful, clearly showing immense confidence in his developer.

Yang Sen and Old Bai turned their gazes toward Liu Guodong. At this moment, the head of the Forensic Identification Office needed to take a stand.

Liu Guodong frowned. "I'll make the call to use the fingerprint developer Lu Chuan prepared. If there are any problems, I'll take the responsibility!"

"What do you mean 'you'll take the responsibility'? I agree too. If anything goes wrong, come find me."

Old Bai smiled. "I'm at an age where I'm almost retired anyway; at most, I'll just get a reprimand."

Yang Sen also nodded. "Old Liu, there are only four of us in the Forensic Office."

"Usually, when Old Bai and I arrive late or leave early, you never say a word."

"This involves risk; there's no reason for you to shoulder it alone."

"Besides, if Little Lu could extract clear fingerprints at a fire scene, he won't fail this time either. Let's get to it!"

Lu Chuan suddenly felt a warm current in his heart.

The three men didn't know he possessed a criminal investigation system, yet they still trusted him unconditionally.

This was true recognition.

With all three in agreement, Liu Guodong nodded heavily. "The developer was prepared by Little Lu; he knows its properties best, so you do the spraying."

"Old Bai is responsible for the full video recording. Yang Sen and I will take photos of the developed fingerprints from two different angles!"

Lu Chuan had already tested the spray volume of the small bottle.

He sprayed into the air once more to confirm there were no issues, then aimed at the handlebars of the electric scooter.

"I'm starting!"

Old Bai had already set up the camera to film from the perimeter.

Liu Guodong and Yang Sen stood on opposite sides of the spray bottle.

As the fine mist was released, a miraculous scene unfolded.

On the handlebars, which had previously shown nothing, dense fingerprints appeared.

Furthermore, they appeared in a pale red color.

The black developer had produced pale red fingerprints.

The contrast was incredibly sharp!

Watching the magical transformation before them, the eyes of Liu Guodong and the others burned with excitement. "Little Lu, you can apply for a patent for this developer!"

"Holy crap, Little Lu, you're amazing!"

"Little Lu, my niece really has a 'husband-prospering' face. Are you sure you won't reconsider?"

Lu Chuan: "..."

With Lu Chuan's specialized fingerprint developer, the fingerprint collection work progressed very rapidly.

Moreover, the results far exceeded expectations.

"Seventy-two fingerprints..."

Tsk tsk, Yang Sen clicked his tongue in admiration.

"And three sets of footprints!"

Old Bai took down the camera and began packing the tripod. "We're going to be quite busy this time."

Bai Wenhai was right; although they had won the battle in fingerprint collection, the real heavy lifting lay ahead.

Fingerprint analysis.

With seventy-two fingerprints, some of which were overlapping, the difficulty of analysis was immense.

Liu Guodong and the others were certainly going to be pulling all-nighters for the next few days.

Lu Chuan couldn't stay idle either.

Although he had shortcomings in fingerprint analysis, footprint analysis was his strength.

The footprints collected from the electric scooter's floorboard also had to be analyzed today.

According to news from Action Group Two, since the scooter was stolen, the perpetrator must have been riding it.

Just like looking for a baby in a red-light district—there's no reason to spend all that money only to have someone ask you to solve math problems.

Among the three sets of footprints collected, one should belong to the perpetrator.

"You guys handle the comparison and analysis. I'm going to report the situation to Captain Qin."

***

In Meeting Room No. 1.

The whiteboard was already covered with photos.

The social connections of the deceased, Wang Lin, were somewhat complex.

Action Group One had been investigating for a day, but they hadn't fully grasped the situation.

"This Wang Lin was a lead dancer at the Nightfall Bar."

Sun Jun was providing the background of the deceased. "So far, we've identified only six ex-boyfriends."

"Has the deceased's phone been found?" Qin Yong asked with a frown.

Sun Jun shook his head. "Not yet. The salvage team didn't find the phone or any of the deceased's identification in the reservoir. It's estimated the perpetrator hid it."

"How is the investigation of the surveillance cameras near the reservoir going?"

"Still being screened. No valuable clues have been found so far."

"Ren Qiang, how is the investigation on your end?"

"No eyewitnesses found yet." Ren Qiang sighed. "The area around Xingfu Reservoir is sparsely populated; usually, only recreational anglers go there."

"If the time of death was during the night three days ago, the possibility of finding a witness is low."

"However, we've made some progress in the investigation of the stolen electric scooter."

"The traffic police traced this based on the license plate."

The projector was turned on, displaying a photo of a silhouette riding an electric scooter.

Looking at the somewhat blurry silhouette on the screen, Qin Yong's brow furrowed. "Is there no frontal photo?"

Ren Qiang shook his head. "There's only this one photo, and it was night at the time, so it's very blurry."

"This is an important clue. Ren Qiang, your team must follow up with everything you've got!"

Qin Yong began assigning tasks. "Sun Jun, your group will conduct a thorough screening of the deceased's ex-boyfriends. You need to clarify her social connections in the shortest time possible."

*Bang!*

Just as Qin Yong finished his report, the meeting room door opened, and it was Liu Guodong.

Qin Yong's eyes lit up. The Forensic Identification Office had contributed greatly to recent cases.

In this reservoir body-dumping case, it was the forensic team that had first verified the identity of the deceased.

Qin Yong had originally arranged for Liu Guodong to examine the electric scooter salvaged from the reservoir; seeing him now, there should be good news.

"Old Liu, any findings?"

Liu Guodong did not disappoint Qin Yong. He nodded heavily. "We used some special methods, and the fingerprints from the electric scooter have been fully extracted."

"Yang Sen and Old Bai are currently performing comparisons."

"We also collected three sets of footprints from the scooter's floorboard, and Lu Chuan is analyzing them."

"At the earliest..." Liu Guodong glanced at the quartz clock on the wall, "we can have results by tomorrow morning."

The news from the Forensic Office invigorated Qin Yong.

The other investigators also breathed a collective sigh of relief.

In the recent cases solved by the Criminal Investigation Detachment, the Forensic Identification Office had played a vital role.

Hopefully, they would secure a major win this time.

"Good. Hurry up. The fingerprint information of the deceased's associates will be sent to you immediately."

The investigation into Wang Lin's social network was ongoing.

Fingerprint information for all interviewed individuals had also been collected.

***

In the Forensic Identification Office.

All four were busy.

With seventy-two fingerprints, some of which overlapped, the difficulty of comparative analysis was high.

"Do the individual fingerprints first; analyze the overlapping ones last."

Liu Guodong assigned the tasks. "The scooter was pushed into the reservoir, so the last person to leave fingerprints should be the perpetrator."

"Therefore, even if his fingerprints overlap, they should be the topmost layer, and there's a high possibility they were left individually."

"Prioritize comparing fingerprints collected from more concealed areas like the wheels and the rear seat."

Pushing a scooter into a reservoir involves certain movements; those areas are likely to have been touched.

As for Lu Chuan, he had already begun analyzing the footprints from the floorboard without needing Liu Guodong's instruction.

Compared to previous footprint analyses, the footprints on the floorboard were only obtained as developed photographs due to water immersion.

They were somewhat different from normal footprints.

Of course, the principle of footprint extraction is different from fingerprint extraction.

Lu Chuan's developer was targeted at water-soaked fingerprints; footprint extraction utilized different methods.

Among the three sets of footprints, the traces on the left floorboard were deeper, while those on the right were shallower.

The reason was that when a rider mounts an electric scooter, they step up from the left side.

Upon mounting, the entire body weight is concentrated on the left foot.

Once riding, because most of the weight is supported by the seat, the footprint becomes lighter.

The right footprint received less pressure and was naturally shallower, appearing almost invisible compared to the left.

For Lu Chuan, who only possessed basic footprint analysis skills, this was a significant challenge.

7:20 AM the next morning.

Lu Chuan stretched his arms and let out a long breath as he looked at the sheets of calculation paper on the desk before him.

After a night of battling, he had finally succeeded.