"Master, this developer is very stable. It was a secret technique from an old professor when I was in college, specially used for developing water-soaked fingerprints."
Lu Chuan had no way to explain the source of the skill, so he attributed this fingerprint developer to the old professor.
"But this developer also has a drawback, which is that the developing time is short, only about ten seconds."
"So, we need to record the entire process, and each fingerprint must be photographed within ten seconds!"
Lu Chuan's words were firm, showing that he had great confidence in his developer.
Yang Sen and Old Bai's gaze turned to Liu Guodong, as it was time for the Crime Scene Investigation Office chief to make a decision.
Liu Guodong frowned: "I'll decide to use Lu Chuan's fingerprint developer. Any problem, I'll take responsibility!"
"What do you mean you'll take responsibility? I also agree, if something happens, come to me."
Old Bai chuckled: "At my age, I'm almost retired, at most I would just get a reprimand."
Yang Sen nodded too: "Old Liu, the Crime Scene Investigation Office is just the four of us."
"We usually arrive late and leave early, and you never say anything."
"There's no reason for you to bear the risk alone."
"Besides, Lu could extract clear fingerprints from a fire scene, this time won't be worse, let's begin!"
Lu Chuan suddenly felt a warm flow in his heart.
The three didn't know he had a criminal investigation system, yet they could absolutely trust him.
This was recognition of him.
All three agreed, and Liu Guodong nodded heavily: "The developer was mixed by Lu, he is most familiar with its properties, so let him do the spraying."
"Old Bai will handle the full video recording. Old Yang and I will take photographs from two angles of the developed fingerprints!"
Lu Chuan had already tested the spray volume of the small spray bottle.
He sprayed into the air one more time to confirm there were no issues, then aimed at the electric scooter's handlebar.
"I'm starting now!"
Old Bai had already set up the camera, filming from the periphery.
Liu Guodong and Yang Sen stood on either side of the spray bottle.
As the fine mist spread for a moment, a miraculous scene appeared.
Where previously there was nothing on the handlebar, densely packed fingerprints emerged.
And they appeared in light red.
The black developer revealed light red fingerprints.
The contrast was very clear!
Seeing the magical change in front of them, Liu Guodong and the others had eager eyes: "Lu, your developer could be patented!"
"Damn, Lu, you're amazing!"
"Lu, my niece really has a prosperous look, won't you reconsider?"
Lu Chuan: "..."
With Lu Chuan's specially made fingerprint developer, the fingerprint collection work progressed very quickly.
Moreover, the results far exceeded expectations.
"Seventy-two fingerprints..."
Tsk tsk, Yang Sen clicked his tongue in admiration as he spoke.
"And three sets of footprints!"
Old Bai took down the camera and started packing up the tripod: "This time, we've got our work cut out for us."
Bai Wenhai was right, while fingerprint collection won a victory, the real work was just beginning.
Fingerprint analysis.
Seventy-two fingerprints, some overlapping, made the analysis very challenging.
Liu Guodong and the others were bound to pull all-nighters recently.
Lu Chuan couldn't be idle either.
Even though he had weaknesses in fingerprint analysis, footprint analysis was his strength.
The footprints collected on the electric scooter's pedal also needed to be analyzed today.
According to news from Action Group Two, since the e-scooter was stolen, the culprit must have been riding it.
Just like spending money on someone in a brothel alley, there's no reason to have them do math problems, right?
Among the three sets of footprints collected, one set should belong to the culprit.
"You guys perform the comparison analysis, I'll go report to Captain Qin."
Conference Room One.
The whiteboard was already covered with photos.
The deceased, Wang Lin, had somewhat complex social connections.
Action Group One had already investigated for a full day, but hadn't fully understood yet.
"This Wang Lin was the lead dancer at Night Bar."
Sun Jun was providing the background details on the deceased: "So far, we've only identified six ex-boyfriends."
"Did you find the deceased's phone?"
Qin Yong frowned as he asked.
Sun Jun shook his head: "Not yet, the salvage team didn't find the phone or any ID belonging to the deceased in the reservoir, it's probably hidden by the killer."
"How's the investigation of the surveillance around the reservoir?"
"Still under investigation, no valuable clues found so far."
"Ren Qiang, how's your side of the investigation going?"
"We haven't found any eyewitnesses yet."
Ren Qiang sighed: "Happy Reservoir is sparsely populated, usually only anglers go there."
"If the deceased died three nights ago, finding witnesses is unlikely."
"However, we've made some progress on the stolen electric scooter investigation."
"The traffic police have identified this based on the license plate."
The screen projector lit up, showing a photo of someone riding an electric scooter from the back.
Looking at the somewhat blurry back on the screen, Qin Yong furrowed his brows: "No front-view photos?"
Ren Qiang shook his head: "Just this one, and it was nighttime, so the photo is very blurry."
"This is an important clue, Ren Qiang, your team should follow up with full force!"
Qin Yong started assigning tasks: "Sun Jun, your team needs to carry out detailed investigations into the deceased's ex-boyfriends and clarify their social connections as soon as possible."
Bam!
Just as Qin Yong finished reporting, the conference room door opened, and it was Liu Guodong.
Qin Yong's eyes lit up. Recent cases heavily relied on the work of crime scene investigation.
This reservoir dump case was also identified by Crime Scene first.
Qin Yong originally had Liu Guodong inspect the electric scooter salvaged from the reservoir, and it seemed there was good news now.
"Old Liu, any discoveries?"
Liu Guodong did not disappoint Qin Yong, nodding heavily: "We used some special methods, and fingerprints have been fully extracted from the scooter."
"Yang Sen and Old Bai are doing comparisons."
"We also collected three sets of footprints from the scooter's pedal, and Lu Chuan is analyzing them."
"At the earliest..." Liu Guodong glanced at the quartz clock on the wall: "Results can be out by tomorrow morning."
The news from the Crime Scene Investigation Office invigorated Qin Yong.
Other investigators couldn't help but breathe a sigh of relief.
In recent cases solved by the Criminal Investigation Team, Crime Scene played an important role.
Hopefully, this time they can stand tall as well.
"Alright, proceed quickly, the fingerprints of the deceased's acquaintances will be sent to you shortly."
The investigation into Wang Lin's social network continued.
All interrogated individuals' fingerprint information was also collected.
Crime Scene Investigation Office.
All four were busy.
Seventy-two fingerprints, with some overlapping, made the comparison and analysis very difficult.
"Start with individual fingerprints, analyze overlapping ones last."
Liu Guodong distributed tasks: "The scooter was pushed into the reservoir, the last fingerprints left should belong to the culprit."
"So, even if his fingerprints overlap, they should be on top, and likely to be left alone."
"Especially fingerprints collected from hidden areas like the wheels and rear seats, prioritize these."
Analyzing pushing the scooter into the reservoir and the culprit's actions, these areas are likely points of contact.
As for Lu Chuan's side, without Liu Guodong's arrangements, analysis of the footprints collected on the scooter's pedal had already begun.
Compared to previous footprint analyses, the footprints collected on the pedal, due to water immersion, are just developed images.
There are some differences from normal footprints.
Of course, the principle of footprint extraction differs from fingerprint extraction.
Lu Chuan's developer targets water-soaked fingerprints, so some other methods were used for footprint extraction.
Among the three sets of footprints, the left pedal had deeper marks and the right pedal lighter ones.
The reason is that the rider mounts the scooter from the left side.
When mounting, the whole body weight is concentrated on the left foot.
After riding, with most of the weight supported by the seat, the print would be lighter.
With the right footprint receiving less force, it naturally would be lighter, almost invisible compared to the left side.
This posed a challenge for Lu Chuan, who only had basic footprint analysis skills.
The next morning at 7:20.
Lu Chuan stretched his arms, looking at the desk full of calculation draft papers, and exhaled a long breath.
After a night of hard work, he finally succeeded.