As long as it is done by people, it will definitely leave traces.

This is something I have always agreed with since I joined the police, and it has always been the motto of my career as a criminal policeman.

The clue is there, and if you don't go to it, it won't come to you. If you don't find clues, you can only say that you are still far from the scene of the crime.

This is the third time we have rushed to the crime scene in Qinghe to do on-site investigation work, and we finally found clues in the opposite direction of the crime scene.

This cement road has been ignored by us before, but I didn't expect that it is this place that has been ignored by us that there are major clues to the case.

After returning to the Ningzhou City Public Security Bureau, Jiang Tingbai immediately carried out the trace examination.

The top priority was to identify the Huazi cigarette butt we picked up on the side of the road, because Jiang Tingbai had smelled perfume on the cigarette butt.

Perfume can volatilize over time, but the chemical composition of the perfume remains on the cigarette end.

It's just that after a heavy rain, I don't know if I can extract the relevant perfume ingredients.

However, Jiang Tingbai tried atomic absorption spectroscopy and fluorescence analysis one after another, but he did not find the residue on his hand on the cigarette butt, but he was sure that he smelled the fragrance, which must have been left by the murderer.

Jiang Tingbai used an electron microscope to observe, but found no traces of cosmetics, and finally, he used the medium molecule activation analysis method to finally confirm that the fragrance originated from a perfume.

"That's right, it's perfume." Jiang Tingbai showed a very firm smile, a sense of accomplishment, and spontaneously appeared.

Then, Jiang Tingbai put the cigarette butt back in the evidence bag and handed it to a police officer from the trace examination department next to him: "Go and hand this cigarette butt to the DNA room of the laboratory department to see if they can extract saliva DNA from the cigarette butt." ”

"Okay." The police officer took the evidence bag and walked out of the trace examination department.

Jiang Tingbai looked at his back and muttered, "I hope the heavy rain hasn't completely destroyed the saliva DNA on the cigarette butts......"

Subsequently, he handed over the activation results of the Chinese molecules in his hand to the police officer on the side, and asked him to compare the results with the results of the perfume in Liu Xiaoqian's backpack.

Seeing that they were busy, I also wanted to participate in his trace examination work, but Jiang Tingbai only let me watch from a distance on the grounds that I had dust on my body, and did not let me get close to those precision instruments.

I can't help but sigh that we all know a bunch of monsters, all of them are workaholics.

Forensic doctor Ren Qiushi is not smiling when he does autopsy work, he is extremely serious, and he usually pretends to be crazy and stupid, like a neurotic and schizophrenic patient.

Xue Hang has always been cold, I've known him for so long, I haven't seen him laugh once.

And then the old dog Jiang Tingbai, treats those trace examination instruments like his wife, others can't touch it, and he has never had a girlfriend, is this the reason......

"What do you want?" Jiang Tingbai asked me while working.

I came back to my senses, smiled faintly, and said slowly, "I think you want to talk about a psychopath. ”

"Me? Am I mentally ill? Jiang Tingbai asked in confusion, he never turned his head to look at me, and kept measuring the footprint photos in front of him repeatedly.

He was doing stride reasoning, inferring the height, weight, age, and gender of the owner of the footprints based on the depth, size, and length of the footprints.

This is a very important aspect of trace examination, and it is also a very important part of the detection of criminal cases from ancient times to the present.

Song Ci, the father of forensic science, emphasized in the chapters of "Collection of Grievances" and "Self-hanging" that it is necessary to pay attention to the investigation of the scene of "self-hanging", "if it goes through mud and rain, it is necessary to see whether the deceased is barefoot and wearing shoes, and whether there are footprints printed on his steps."

In the chapter "Drowning", it is said, "If you stumble, you must look at the marks of the stumbling foot." ”

Jiang Tingbai is an expert in trace examination, and a footprint will definitely not be difficult for him.

"It's a pair of sneakers, it's a size 43, it's a new pair of shoes, and the soles aren't worn." Jiang Tingbai slowly opened his mouth and said seriously.

I didn't answer because I knew he hadn't finished yet.

Jiang Tingbai paused slightly, and then said, "The suspect is a man, about thirty years old, and the fluctuation will not exceed two years old. He is about 1.75 meters tall and weighs about 70 kilograms. ”

Jiang Tingbai recorded all his results, then stood up and handed them to me with his own hands.

"Is it reliable?" I took the materials in my hand and looked at him carefully.

Jiang Tingbai smiled slightly and said lightly: "You have to believe in science." ”

As soon as he finished speaking, the police officer behind him spoke: "The perfume has come out, and the perfume on the cigarette butt is the same as the molecular arrangement of the perfume ingredients in the bottle of perfume in Liu Xiaoqian's backpack, which is the same chemical composition." ”

"Great!" Jiang Tingbai cheered loudly.

"As long as the DNA room of the laboratory can detect the killer's saliva DNA, we will lock down this suspect who helped commit suicide." At this time, I also felt very excited, and subconsciously raised my voice.

Before I knew it, it was another busy day, and the time came to the afternoon again.

After a while, Lin Zifan, Li Meng, and Xue Hang all ended their investigation and visit work today and all returned.

"I'm tired to death, and after walking for two days, my legs are thin." Li Meng sat down in his chair very tiredly, took the cup and drank a big sip of water.

"Thinness isn't what you've always wanted?" Jiang Tingbai quipped.

"I think you should go out and investigate, you will definitely lose weight, you see you are now, and you have gained weight again." Li Meng saw Jiang Tingbai and said with a smile.

"Everyone has worked hard, today Jiang Tingbai and I went to the crime scene in Qinghe again, this time there was a major discovery, we found the suspect's footprints and cigarette butts." I spoke.

"Really?! That's great! Lin Zifan was very excited.

"How are you all, any clues?" I nodded, and threw the topic to everyone.

Lin Zifan spoke first: "I took the criminal police team and the police of the Qinghe Branch to investigate and visit the households near Qinghe, but the visit was not comprehensive, and I will continue to go again tomorrow." At present, there are no valuable clues, everyone's life is relatively good, and no one's life has been hit recently, and there are thoughts of suicide. ”

"I have planned a total of three routes from the city center to the scene of the crime in Beishan, all three routes are in the urban area, and after leaving the urban area, they converged into one route, and they are still investigating and monitoring along the road, and the progress has passed halfway, and the investigation will be completed tomorrow." Xue Hang said seriously.

After everyone finished speaking, we looked at Li Meng together.

Li Meng calmed down and said slowly: "Ma Junxu is gone......"