CHAPTER 74: CHAPTER 74: TIRE MARKS

The world is always full of unpredictability, chance, and the unforeseen.

No one knows what will happen to them tomorrow.

Song Kun was a veteran of the Criminal Investigation Team in the High-tech Zone, having trained many detectives.

He was also familiar to most people in the Criminal Investigation Team.

Even officers at the crime scene, if they hadn’t met Song Kun in person, had mostly heard of his name.

Maybe yesterday, or even earlier today, there were still people envying Song Kun’s imminent retirement.

But what they saw today was nothing but a cold corpse.

For many members of the Criminal Investigation Team in the High-tech Zone, this was a scene hard to accept.

Although Qin Yong had personally arrived at the scene, the main command was still with the captain, Yuan Shaokang.

After all, Song Kun was his man, and this was yet another traffic incident.

The mood affected by the case was significant, but in reality, there was no need for the criminal investigation to intervene.

It’s just that now the pursuit of the hit-and-run driver has been involved, making it more complicated than an ordinary traffic accident.

However, with current methods, a vehicle that causes a fatal hit-and-run is unlikely to get away.

It can definitely be found, and since the deceased is a detective, the traffic police will surely give their full effort.

Liu Guodong followed Lu Chuan’s voice and walked over: "Have you found any problems?"

Old Liu’s mood was also heavy.

He too will have a day when he retires.

But who can guarantee they’ll live to see that day?

"Here, there’s a tire scorch mark."

Lu Chuan squatted on the ground, using tweezers to scrape the asphalt road surface. His basic tire trace analysis skills quickly allowed him to determine the relevant information left by the scorch mark: "Rubber friction marks left by the tire when the vehicle accelerates suddenly, scraping the ground."

Liu Guodong’s head buzzed at this.

"Are you sure it’s a tire mark left by acceleration?"

Lu Chuan nodded affirmatively: "The marks left by braking are different from those made by acceleration, as the friction directions are the opposite, so the friction directions of the tire marks are also different."

Liu Guodong raised his head along a spot of the mark on the ground, looking toward the collision point of Song Kun’s car accident.

"Do you suspect it wasn’t...an accident?"

From this direction, the vehicle would travel in a straight line right to the collision point.

"Ding!"

"Advanced Mission: Complete a qualified tire trace analysis, uncovering the truth behind Detective Song Kun’s death."

Lu Chuan used tweezers to pick up a small part of the scorch mark, bringing it up to his nose to smell: "It’s possible."

"The smell of the scorch mark is very strong, left no more than three hours ago."

"Also," Lu Chuan stood up and pointed to the sandy land beyond the curb: "There’s a clear friction mark in the sandy soil here."

"This should be a four-wheel drive vehicle, with traction marks from all four tires."

"Additionally, the tread patterns are consistent and the wear is similar."

"There aren’t a lot of vehicles on Longjiang Road, so the probability of two cars of the same model appearing in a short time is relatively low."

Opening his portable crime scene investigation box, Lu Chuan used a cotton swab to soak up the rubber residue from the scorch mark: "I’ll collect some of the rubber residue from the tire brake marks at the collision point later for a comparative component analysis."

"Combining this with the patterns in the tire traces, we can determine if this vehicle was the one that killed Song Kun."

Lu Chuan’s discovery made Liu Guodong realize the seriousness of the situation.

Traffic accidents and intentional murder are not the same thing.

Moreover, if Song Kun did not die due to a traffic accident, then who was it that intentionally wanted to kill a soon-to-retire detective?

Is it because of a case Song Kun was currently handling?

Had he discovered something significant?

Or was it revenge by someone Song Kun had previously arrested, now released?

Or could it be a personal vendetta in his life?

The consequences of each possibility vary tremendously.

Or rather, they’re worlds apart.

If it’s an accidental death, it’s just an act of God.

But if it was murder, and it stemmed from a personal motive, it’s an ordinary murder case.

But if it was premeditated revenge, then Song Kun died in the line of duty, and he’s a martyr.

"Lu, you handle the scene investigation here first, I’ll report to Captain Qin."

Lu Chuan nodded solemnly.

Actually, when he first arrived at the scene, Lu Chuan didn’t think too much.

It was just because traffic police were already measuring the tire mark data near the collision point, so he didn’t go forward.

After all, expertise matters.

The traffic police’s experience in handling traffic accidents is certainly richer than that of the criminal investigation team.

So, Lu Chuan casually wandered around the perimeter, walking back a few steps against the direction of vehicle travel.

But unexpectedly, he found these details.

A minute later, Qin Yong ran to the corner of the road, accompanied by the traffic police captain, Zhang Yongzhi.

"Lu Chuan, can you confirm?"

Having just finished collecting rubber residue, Lu Chuan was now photographing the tires.

"Captain Qin," putting down the camera, Lu Chuan opened the browsing window: "This is the tread pattern from the tire marks here, and it should be consistent with the pattern left by the brake marks near the collision point."

On the asphalt road, although the brake mark of the vehicle is a dark scorch mark, because of the tire’s own pattern, the depth of the scorch mark has subtle differences.

To the trained eye, these differences in depth aren’t merely marks—they actually correspond to the tire’s tread pattern.

Moreover, at the starting and ending points of the track, especially at the end of a braking mark, the layer of rubber residue left due to the high-temperature friction when the vehicle comes to a stop is often very clearly imprinted.

Upon receiving Lu Chuan’s confirmed answer, Qin Yong looked extremely grim.

Murdering a detective, and disguising it as an accident at the scene of a car crash.

Who would be so bold?!

"Any other clues?"

Lu Chuan nodded: "I just did a preliminary analysis of the tire marks. Judging from the color of the tire marks, the vehicle involved should be a passenger car, and based on the initial tire width measurement of 265, it should be a tire used by a large sedan or SUV."

Seeing Qin Yong frown, Lu Chuan continued to explain: "Vehicle tires have certain specifications. Passenger vehicles, construction vehicles, and cargo trucks have different uses, and their tire specifications are also different."

"The difference in tire specifications lies in the rubber material, and the color of the scorch marks varies somewhat."

Tire traces can serve as forensic evidence primarily because tire specifications are fixed.

Under normal conditions, tires are distinguished according to vehicle types.

And fixed English letter markings exist on the tires.

For instance, the English letter ’PC’ represents passenger car tires, which are commonly used in both regular sedans and SUVs.

’LT’ stands for light truck tires, ’TB’ for truck and large bus tires, ’AG’ is the symbol for agricultural vehicle tires, ’OTR’ is for construction vehicle tires, ’ID’ for industrial vehicle tires, ’AC’ is for airplane tires, and ’MC’ is for motorcycle tires.

Lu Chuan pointed to the tire marks on the sandy land underfoot: "Based on the distance between the front and rear tires, the measured wheelbase is 2850, and all four wheels have traction marks, so it should be a four-wheel drive vehicle."

Lu Chuan pointed to Song Kun’s distant body: "I just heard the forensic doctor say that the direct impact on Song Kun’s body was above the waist, near the chest position."

"From this height, it’s estimated that the vehicle involved should be an SUV."

"The scattered bumper fragments on the road are white, so it’s initially determined to be a white four-wheel-drive SUV."

Lu Chuan thoroughly entered the zone: "I’m not particularly familiar with vehicle models, but SUVs with a wheelbase of 2850 shouldn’t be that many. We should be able to roughly lock onto the vehicle brand."

Lu Chuan’s thoughts became increasingly clear, his focus intensified, not noticing how shocked Qin Yong and Zhang Yongzhi now looked.