You went on a blind date and presented an A-level wanted criminal as a meeting gift?

The main office of the Major Crimes Unit at the Beijing Police Headquarters.

The atmosphere was oppressive.

The entire police station was completely sealed off; not even a fly could get out. The technical staff, fully equipped, were fumbling around in the ventilation ducts on the third basement level with various instruments.

Not long after, an expedited test report was delivered to Su Qingge.

"Captain Su, we've figured it out." Old Wang from the technical department, covered in sweat, pointed to the data on the report and said, "Someone has coated the filter screen of the negative pressure machine with a high concentration of slow-release corrosive agent. This corrosive agent doesn't usually react, but as long as it encounters certain airflow vibrations, it will rapidly dissolve the fiber structure of the filter screen within seconds, causing the negative pressure to fail."

Su Qingge's face turned ashen. She slammed her hand on the desk, making the water glass on it vibrate loudly.

"How dare they! They've even set their sights on the headquarters' biochemistry lab! Where's the surveillance footage? Get the footage of everyone who's entered or left the police station over the past three days, don't even let the cleaning staff get away with it!"

Several young criminal police officers immediately slumped in front of the computer, their eyes bloodshot, staring intently at the dozens of surveillance camera feeds displayed on the split screen.

Time passed by, second by second.

The dozens of people in the Major Crimes Unit painstakingly analyzed every frame of the surveillance footage from the past three days.

The result, however, was extremely disappointing.

"Captain Su... we found nothing." An old detective rubbed his sore eyes, his tone filled with deep discouragement. "The other party is an extremely professional counter-surveillance expert. He perfectly avoided all the blind spots of the cameras in the lobby, corridors, and basement. Even if he occasionally captured a silhouette, he was wearing a hat and mask, making facial recognition impossible."

"That's impossible!" Su Qingge gritted her teeth. "Anyone who's been to a police station will definitely leave a trace!"

The veteran detective sighed, "That's true, but we've really hit a dead end with surveillance footage. Without video evidence, without witnesses, how are we supposed to investigate this case?"

The entire Major Crimes Unit fell into a deathly silence, and everyone felt a deep sense of powerlessness.

Just then, the office door was pushed open.

Lin Chen walked in carrying a steaming cup of brown sugar ginger tea.

Lin Chen handed the ginger tea to Jiang Tingxue, his voice gentle: "Drink this to warm your stomach. The poison gas damaged your respiratory tract earlier, so try not to talk too much these next few days."

Jiang Tingxue nodded obediently, holding the cup in both hands, her eyes full of dependence.

After settling Jiang Tingxue in, Lin Chen turned around, his gaze sweeping over the gloomy-faced members of the Major Crimes Unit, and chuckled, "What? One counter-investigation expert has stumped you all?"

The veteran detective smiled wryly: "Consultant Lin, it's not that we're not careful, it's just that this person is too cunning. There's not even a clear picture of his face in the surveillance footage, and the scene has been cleaned up spotlessly."

"Checking the surveillance footage? That's the dumbest way."

Lin Chen strode forward and walked straight to the maintenance port in the corner of the office hall that connected to the ventilation duct in the basement.

At that moment, a system notification sounded in his mind.

[Ding! Host detected conducting on-site investigation; God-level olfaction and God-level psychological profiling automatically activated!]

Lin Chen stood in front of the inspection port, closed his eyes slightly, and took a deep breath.

The air was filled with the smells of disinfectant, printer ink, and the sweat of the police officers. But amidst this cacophony of odors, Lin Chen's god-like sense of smell instantly picked out a faint, unusual scent that didn't belong to the police station.

"The corrosive agent contains a trace amount of rosin." Lin Chen said with his eyes closed, his voice calm yet carrying an undeniable power. "It also has a peculiar earthy smell... cold, damp, with the earthy odor of a place that has never seen the sun."

Su Qingge was stunned: "The smell of soil? The police station is cleaned every day, where would the smell of soil come from?"

"This isn't ordinary soil." Lin Chen opened his eyes, his gaze sharp as a knife. "This is old pit soil brought up by a Luoyang shovel. This person often digs holes underground, or rather, he spends most of his time in some abandoned underground cave."

The officers from the Major Crimes Unit looked at each other in disbelief. Could someone really identify the soil from an old mine just by smelling it? That was simply unbelievable!

But Lin Chen ignored their shock. With the help of the god-level psychological profiling, his brain was rapidly reconstructing the suspect's movements at that time.

He crouched down, his gaze fixed on an inconspicuous spot on the edge of the aluminum alloy access panel.

"Old Wang, bring the UV lamp and developing powder over here, and scan this spot." Lin Chen pointed to the edge.

Old Wang from the technical department quickly ran over and followed Lin Chen's instructions to perform a series of operations.

The next second, everyone gasped!

Under the ultraviolet light, a very shallow, two-centimeter-long rubber shoe sole friction mark was clearly visible on the edge of the inspection port!

"This... how did you find such a tiny trace, Consultant Lin?" Old Wang's eyes almost popped out of their sockets.

Lin Chen stood up and dusted off his hands: "It's simple, just logical deduction. He's about 1.75 meters tall and rather thin. Most importantly, he has an old injury in his left leg, causing uneven weight distribution. When he stands on the stool and reaches out to apply the corrosive agent, his left leg will subconsciously rub outwards to maintain balance."

Lin Chen looked at Su Qingge: "Check on the new worker who delivered bottled water to the bureau three days ago."

Su Qingge immediately realized: "The water deliveryman? Why him?"

"Because when he came in, the bucket of water he was carrying was the wrong weight," Lin Chen said coldly. "A normal bucket of water weighs 18.9 liters, which is about 19 kilograms. But when he carried that bucket of water through the corridor, the angle of his shoulders and the tension in his muscles were at least 3 kilograms lighter than normal. Those missing 3 kilograms of water were replaced with corrosive agent in a waterproof bag."

The entire office was deathly silent.

Everyone stared at Lin Chen as if he were a monster. Was he even human? Could he even tell the tension in someone's muscles when they were lifting a bucket of water?

Su Qingge immediately ordered, "Quickly! Go to the logistics department to verify the water deliveryman's information!"

Less than two minutes later, the detective in charge of checking the files shouted, "Captain Su, we found it! There was indeed a new water deliveryman three days ago named Zhang Qiang. But... his ID card is fake, and he disappeared after delivering water this morning. The water station can't contact him either!"

"They ran away?" Li Mingyu stamped his feet anxiously. "In this vast sea of ​​people, where are we supposed to find someone using a fake identity?"

Lin Chen picked up the car keys on the table and let out a cold laugh.

"Trying to run? He can't wash off that old, earthy smell. Mingyu, grab your gear and call the SWAT team."

Li Mingyu perked up: "Brother Lin, where to?"

"The abandoned brick kiln in the southern suburbs." Lin Chen strode towards the door. "In the entire capital, only the unique clay there can produce that special earthy smell."