Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

At the scene, the deceased was lying on the sofa with his back facing up.

The wound on the neck was clear and deep.

Lu Chuan was surveying, and Wang Hao was taking notes.

"The carotid artery was incised with a sharp instrument, and the wound was about 6 cm long and 4 cm deep..."

Lu Chuan opened the deceased's eyes: "The pupils are dilated, the lens is not cloudy, and there is no congestion..."

At this moment, Lu Chuan had completed the site survey from the entrance door to the sofa in the living room.

Some fingerprints and footprints were found, and the collection has been completed. However, it is still uncertain whether these fingerprints and footprints belong to the murderer.

Of course, judging from the detection of the first three cases, these footprints and fingerprints should not be able to identify the murderer, otherwise the Binhai City Criminal Investigation Detachment would have solved the case long ago.

Now Lu Chuan is focusing on the initial investigation of the condition of the body.

The cause of death of the deceased was initially determined to be carotid artery rupture and fatal hemorrhagic shock resulting from a single stabbing.

I groped the top of my head, and sure enough, there was something hard at the Baihui point.

Lu Chuan pulled back his hair and saw a naked nail cap: "A steel nail was found at the Baihui point."

Wang Hao's hand shook, and sure enough, he was still the murderer.

The first three corpses were all identified by Wang Hao and the forensic doctors from the BZ City Criminal Investigation Detachment.

"How about it? Are they the same as the nails on the heads of the previous corpses?"

Wang Hao just took a look and knew that they were exactly the same.

"The 3.5cm long ordinary steel nails are all new and not rusty. We checked that these nails are sold everywhere and we can't find the source at all."

"And judging from the shape of the wound and the traces of bleeding, it seems that the murderer used a hammer or other tools to hit the victim after killing him."

Lu Chuan recognized this judgment.

Pulling back his hair, he found that the wound on Baihui point showed no stress reaction and was probably a post-mortem injury.

"What's the difference between the wound on the neck?"

Wang Hao stepped forward and gestured: "For the first corpse, we found two wounds on the neck of the deceased. One of them cut the carotid artery of the deceased, which eventually caused the victim to die of hemorrhagic shock. However, there was another wound that was not cut. Broken carotid artery."

"Injured during life or after death?"

"Anti-mortal injuries, ectropion of the tunnel, and obvious stress reaction."

"We didn't pay special attention to these two wounds at the beginning, but the forensic doctor and I also made a more detailed comparison of the wounds on the second and third bodies."

“The second time he killed someone, he only used one knife. Although the position of the knife was not particularly accurate and only 2/1 of the carotid artery was cut, by the time of the third corpse, the entire carotid artery was completely cut. "

Wang Hao pointed to the fourth corpse under him: "Look at the wound on the victim's neck now. The cross-section area is small and the depth is deep. It shows that the other party is very skilled and the knife was stably and hard at the carotid artery."

"Obviously, the other party is constantly improving, and his killing techniques are becoming more and more proficient."

Lu Chuan exhaled.

To a certain extent, killing someone is no different than killing a chicken.

The first time anyone kills a chicken, it takes a lot of effort to slit the neck and bleed the chicken.

But after killing a few chickens, this action will become very skillful, and you can catch the chickens, draw the knife and bleed them in one go.

It is obvious that after the suspect in this serial case killed the first person, he continued to become more proficient and improved in his crime techniques.

This is the biggest headache for all criminal police officers handling cases.

All serial murderers or criminals who have killed multiple times will become increasingly difficult to catch if they don't catch them the first time. In the past few years, there were many similar cases pending in various places.

Because when the other party committed a crime for the first time, he was in a state of high tension, both in terms of technique and psychology. His techniques were unfamiliar and his psychology was immature. It was inevitable that he would be afraid when killing someone.

Emotional instability will cause the other party to make omissions during the killing process, or when handling the scene later.

This is also when it is easiest for the police to find flaws.

However, if the suspect is not caught the first time, the other party will definitely review the entire process after killing the person, and then make adjustments to the loopholes that were not noticed at the time.

By the time he commits the crime for the second time, this loophole will basically disappear. If he commits the crime again, his techniques will become more and more proficient.

Fifteen years ago, a horrific serial murder case of eight people occurred in the neighboring province.

The opponent's proficiency in killing is at the end. I passed the victim on the street and cut my throat with a hand knife.

The whole transformation time does not exceed 5 seconds, and the killing is completed.

There is no way to solve this kind of case.

Wang Hao had participated in the previous three cases and investigated the scenes, so he had a very intuitive understanding of the murderer's proficiency in killing techniques.

Lu Chuan continued to conduct a superficial examination of the body: "There were three stab wounds on the abdomen, one on the navel, the length of the incision was 5 cm and the depth was 1.2 cm."

"There was a puncture wound in the kidney area of ​​the left lower back."

"There was a stab wound below the left rib, but it was not punctured."

"The stab wounds to the kidney area and below the left rib, with obvious wound valgus, were caused by the deceased during his lifetime."

"But...the scratch on my belly button..."

Under different conditions of human body function, the skin responds differently to stress wounds.

The victim had a puncture wound on the kidney area of ​​his left lower back and a stab wound below his left rib, showing a very obvious stress reaction.

But the scar on the belly button showed a stress reaction, but the bleeding was not large.

"It should have been the stab wound left by the murderer when the deceased was dying..."

"The rigor mortis had not yet reached its peak. Combined with the body temperature and the opacity of the eye lens, the preliminary estimate of the time of death was 1: a.m. yesterday."

……

The examination of the corpse took the longest time. While Lu Chuan was investigating the situation, he and Wang Hao learned about the previous three cases and some conditions of the victim's corpse.

"In the first three cases, we found blood stains in the sink at the scene. We suspect that the murderer washed the blood on his body or hands after killing the person."

"Did you take trace evidence?"

"No, we don't have equipment for detecting trace evidence."

Standing next to the sink, Lu Chuan opened the leak below.

Sure enough, some blood stains were also found.

"The other party most likely wore gloves when he killed the person. When cleaning, whether they were wearing them or not, it is very likely that some hair or dander on the other party's body was left behind."

"I'll collect some trace evidence first, and the forensic team can come in."

"Yes!"

The entire on-site investigation work lasted until about seven o'clock in the afternoon.

However, the relevant results have not yet come out. The time given by Lu Chuan is tomorrow morning at the earliest. (End of chapter)