Xu Kuan and Du Qin are junior high school classmates, and they just attended a class reunion together the day before yesterday, and now they are both dead.

And they all died in accidents, but we have already found a point from the cause of Du Tan's death, and now we are characterized as killing him.

"Lao Qin, I'll leave the rest to you, I'll go back to the forensic department first." Ren Qiushi patted me on the shoulder and turned to leave.

I suddenly realized that I didn't seem to care so much about the smell of corpses on his body.

It's strange to say, when Ren Qiushi is fine, the smell of corpses on his body is always very strong, but every time I work, I can't smell the smell of corpses on his body again.

After Ren Qiushi left, Xue Hang walked straight towards us and asked in a deep voice, "Team Qin, do you want to go to the rooftop to have a look?" ”

I looked up at the building, nodded, and walked into the staircase with Xue Hang.

There was no elevator in this building, and there was no lock on the roof, so we walked all the way up the stairs to the rooftop.

When I came to the rooftop, the autumn breeze suddenly rose. It's not cold in the heights, and it's not only windy, but also unusually cold.

The roof is surrounded by walls more than half a person high, and in the wall directly in front of us, there is a huge gap, and it seems that the fallen cement brick is here.

"Has this cement brick fall been inspected?" I walked to the fence of the rooftop and poked my head out to look down, and directly below us was the scene of the crime.

And the cement brick that killed Xu Kuan fell off from here.

"I have already called Jiang Tingbai back, and this time he will personally lead the team to inspect here." Xue Hang said in a deep voice.

I nodded, for the old dog Jiang Tingbai, we trust his ability very much. This is an accidental homicide case of a falling object that seems to have a falling wall, and it must be carefully investigated.

Because, if the murderer smashed this wall and caused the wall to fall off, it was not an accident, but a well-planned murder.

I crouched in front of the gap in the wall, and wiped the edge of the gap with my fingers, and the wall was indeed a little loose, and there were large cracks that spread all around the wall.

This building is an old building in Ningzhou City, but according to relevant regulations, the use time of this building is far from enough time to become a "dangerous building".

"There are four walls here, why is this one the only one with such a huge crack?" Li Meng looked around the rooftop for a week, and suddenly said.

After listening to her, Xue Hang and I also stood up and carefully inspected the four walls along the rooftop, although the other three walls also had cracks to varying degrees. But it is only the cracks on the surface of the wall, and the degree is not serious.

Not to mention that the whole wall is falling off, even if the wall skin is falling off, it may be very difficult.

"It seems that this is another homicide disguised as an accident, but we don't have direct evidence yet." Xue Hang thought about it and said lightly.

"The evidence will be there soon, as long as we find out who called Xu Kuan downstairs, plus the old dog will come over with the technical team to investigate after a while, if nothing else, this must not be an accidental killing." I said seriously.

Then, I carefully described to them what I was thinking at this time-

"If the murderer wants to kill Xu Kuan, he will definitely do something to the wall of the rooftop here in advance, and in the same way, he must let Xu Kuan stand exactly downstairs corresponding to the wall where he has done his hands and feet, only in this way can the murderer ensure that the wall falls off and hits Xu Kuan's head.

Therefore, the murderer will definitely contact Xu Kuan and ask him here. Xu Kuan works in a mobile phone store and is responsible for the sales of mobile phones. Xu Kuan's backpack happened to have a brand-new unopened mobile phone, which also shows that the murderer should have invited Xu Kuan here as a buyer. ”

"This kind of difficulty coefficient is too high, how can the murderer guarantee that Xu Kuan will definitely stand in the predetermined position without any difference. How can you guarantee that at the moment when the wall falls off, Xu Kuan will honestly stand in place. According to the analysis of psychological common sense, when a person is waiting for another, there will be a kind of impatience of anticipation in his heart, people will look around, they will pace around for a short distance, and they will not honestly stand still in place. Li Meng raised his own questions.

Indeed, the murderer's method of killing Xu Kuan is much more complicated than the method of killing Du Tan, and it must be particularly precise, during which no step can be missed, and there can be no deviation from the high-altitude falling objects, which carries too much uncertainty.

But no matter how uncertain there is, at least the killer did, and it was exactly the same.

The murderer's purpose was simple, to disguise the killing method as an accident. In this way, as long as they do not leave flaws, the police will not be able to investigate.

There is no absolute perfect crime in the world, as long as it is done by people, it will definitely leave clues. Any subtle clue will be infinitely magnified, and finally become an absolute flaw in the perfect crime.

"The murderer must have prepared in advance, even starting to destroy the wall a few days ago. But with such a strong cement brick wall, what tools will the murderer use? Li Meng suddenly muttered.

She's right, and that's exactly what we need to consider, the killer uses tools to destroy the wall, and to make sure that the wall doesn't fall off in advance and cause the matter to be revealed. And the time it takes to break the wall, especially the loud noise made during the destruction of the wall, will definitely be heard by the residents of this building.

"You say, could the murderer be the occupant of this building? Otherwise, a stranger suddenly appears on the roof of your house and is still trying to destroy the wall, who would agree. Xue Hang pondered for a while, and suddenly came up with an idea.

I nodded, agreeing with him, and said seriously, "It's possible, but it's unlikely." The rabbit doesn't eat the grass next to the nest, and the murderer will kill people near his house, isn't this obviously trying to lure the police over? ”

About fifteen minutes later, Jiang Tingbai came to the rooftop with the technical team.

"Old dog, you're here." Jiang Tingbai and I said hello.

Jiang Tingbai nodded, and was about to speak to me, when he was suddenly attracted by the huge gap in the wall in front of him, he walked straight forward and sighed: "Damn, such a big piece." ”

"I didn't expect that." I shrugged my shoulders and said lightly.

Jiang Tingbai calmed down and beckoned the technicians of the technical team to immediately start an on-site investigation of the rooftop, focusing on looking for suspicious fingerprints, footprints and biological samples.

Jiang Tingbai squatted down, looked carefully at the gap in the wall, and suddenly said, "What kind of smell......