Sitting in the office of the Criminal Police Brigade of Qianjin District, Jiang Yuan carefully compared Bai Yuequn's footprints with the bloody footprints at the crime scene and examined them repeatedly.
This is the only disadvantage of footprints. It cannot determine the suspect one-to-one. It can be infinitely close, but it cannot be determined.
Otherwise, if it is the same as a fingerprint, it can be used as irrefutable evidence to prosecute.
The footprints of bare feet can be regarded as fingerprints, but unfortunately most of the time, there are none.
Murderers generally don't kill barefoot.
Although it is not 100% certain, from Jiang Yuan's perspective, this coincidence can basically confirm Bai Yuequn's identity as the suspect.
If it's close to this level and it's not the murderer, then this is just another coincidence.
Considering that the third oldest, Yuan Yutang, is only in his twenties, a penis ground with a vajra pestle cannot produce many lovers and rivals, and the number of people offended by his flirtatious mouth should be limited. In terms of probability, there is murder.
People with similar motives must have similar footprints. How low is the probability?
Therefore, when Lei Xin, the criminal police captain in the forward area, said that there was an alibi witness, Jiang Yuan immediately questioned the witness.
It is difficult to lie about physical evidence, but it is too easy for witnesses to lie.
However, this was also the first time he encountered such a situation, and he was a little doubtful.
What if?
Just when Jiang Yuan frowned and studied the footprints, Huang Qiangmin walked over with a smile.
"Can't you figure it out?" Huang Qiangmin looked at Jiang Yuan.
"It's not that I can't figure it out, but..." Jiang Yuan didn't know how to explain it to Huang Qiangmin.
"I don't know much about technology, let alone footprints. But, what do you mean, Bai Yuequn's footprints are very consistent with the footprints at the scene?" Huang Qiangmin asked.
"Yes." Jiang Yuan pretended to be full of words and kept saying: "The height is the same, even if you wear height-increasing shoes, the shoe size is also the same, even if you wear big shoes; there is also weight and age; I also watched the surveillance video
Here, his stride and gait are basically the same. If it were a stranger..."
Huang Qiangmin smiled and suppressed Jiang Yuan's waving arm, and whispered: "No ifs, it's him."
"Ah?" Jiang Yuan was a little surprised. To be honest, he didn't dare to be so sure.
"It was the CSI effect you told me about before. I think you have a little bit of it now." Huang Qiangmin smiled and said: "Does DNA and fingerprints have to be there to identify the murderer? You have to be 100% sure before you can prosecute.
?If this were the case, how could we handle cases 20 years ago?"
Jiang Yuandao: "So you made a heavy confession at that time?"
"Oral confessions are not 100% accurate, and inducing confessions is not a patent of Americans." Huang Qiangmin waved his hand and said, "There are enough clues."
"Then Captain Lei..."
"He is new to the case and doesn't know much about the case. Moreover, the case occurred in his jurisdiction, so he must have thought more about it. Ignore him now."
"That……"
Huang Qiangmin said: "Don't stare at the footprints now."
"Then what are you looking at?"
Huang Qiangmin said: "You can look at anything. We have a saying in criminal investigation that evidence alone does not stand up. To use my explanation, it means that if the case is completed, there must be more than one piece of evidence. Now, we have actually finished the most difficult part.
That means we found the murderer and now we have to prove it."
Huang Qiangmin clapped his fingers and continued: "Assuming that Bai Yuequn killed the person, let's assume that his alibi is false. The key is, can we prove it? Can we use physical evidence to identify him."
Jiang Yuan immediately pulled out the horn.
Indeed, the murderer of this case left a lot of evidence. As long as these evidences can be linked to Bai Yuequn, the case will be solved.
Presuming someone is the murderer and then proving that he is the murderer is also the most commonly used method in criminal investigation.
In fact, this is the case in most cases. As the same saying goes, an experienced criminal policeman can pick out the murderer of the first murder just by looking at him.
Therefore, burglaries are often more difficult to solve than burglaries - difficult burglaries are caused by the suspects not being serious and not fully prepared. There are also some professional thieves who have not been caught for a long time and become careless easily.
It’s easy to be careless, and with the intensity of the business, it’s easy to make mistakes.
The wife-murder case in Hangzhou and many other wife-murder cases and husband-murder cases all have similar situations.
The police spend most of their time and energy on making arguments.
The murder case of Yuan Yutang is not complicated at all.
Assuming that Bai Yuequn is the murderer, he just did something to create suspicion.
He had changed into shoes that he didn't usually wear, he was not injured at the scene, and there was evidence of alibi, but doing this itself actually involved a lot of work.
And the more you do it, the easier it is to make mistakes.
The easier it is to lock the evidence.
Jiang Yuan couldn't help but recall the autopsy scene a few hours ago.
Yuan Yutang and his ex-boyfriend were both stabbed to death with the same double-edged dagger. The blade of the dagger was very long, at least about 30 centimeters, and the blade was sharp. The most powerful thing was that after more than 30 cuts in total, the dagger
The sharpness has not been reduced.
With such good quality, it would have been an absolute magic weapon in ancient times. Even in modern times, it is only an expensive military dagger.
But in the domestic environment, such a dagger is easy to buy or not easy to buy, so it is relatively easy to leave clues.
Weapon: Military dagger.
Jiang Yuan wrote these two words in his notebook and underlined them.
Huang Qiangmin nodded and said nothing.
He also saw the autopsy report. The military dagger also explained why the murderer killed two people and stabbed him dozens of times without being injured.
Many novice murderers may have never killed a chicken, or at least a medium to large mammal, before killing someone, so they don't know how strong the resistance of human muscle tissue is.
Things like daggers or daggers are completely different from spears and broadswords.
The reaction force of a dagger or short knife is greater. If the technique is wrong, the wrist and the tiger's mouth will bear huge pressure.
After practicing with novices for a while with broadswords and spears, novices will be able to gather all their strength to slash and stab, but not daggers or short knives. Moreover, civilian products will not be so sharp after stabbing them a few times. If they use too much force, they will still be
It is easy to hurt yourself.
In addition, killing people is still very tiring.
To be more precise, stabbing someone with a knife is very tiring.
Just like killing a pig in the village, several big men have to hold it down, tie it up, and struggle.
…
One, two, or three knives are okay, but more than 30 knives are not that easy. The subsequent movements will be deformed, and the probability of making a mistake or injuring yourself will increase.
The sharpness of military daggers can partially solve this problem.
In addition, the calluses on Bai Yuequn's hands clearly looked like they had been practiced... Jiang Yuan even suspected that he had been prepared.
key!
Jiang Yuan wrote these two words in the notebook again and underlined them again.
Yuan Yutang's door lock was not broken, and there were no signs of technical unlocking. Therefore, the murderer opened the door with a key. While Yuan Yutang and his boyfriend were asleep, he first stabbed his boyfriend to death, and then stabbed Yuan Yutang multiple times, causing his death.
.
This is one of the reasons why the list of suspects focuses on relationships between lovers and rivals.
No matter how many people Yuan Yutang works with, he still can't get the key to his home.
Only lovers or love rivals are better suited to get the key.
Bloody clothes.
Jiang Yuan then thought of the murderer's murder process.
The murderer's follow-up treatment of the crime scene was relatively rough. Perhaps because he was in a hurry, he didn't care about the bloody footprints at all. The only way to eliminate the traces was to pour a basin of water over them.
But with the amount of bleeding at the scene, the murderer's clothes must have been stained with blood. He could take a shower and change clothes in the bathroom, but it would be difficult to clean the clothes he changed in a day.
Most people either throw it away, burn it, or bury it.
But no matter what happens, it takes time.
Bai Yuequn still lives in the city center and is under constant surveillance.
Therefore, the place where he can put the bloody clothes is very limited, maybe in a bar or office.
Screening room monitoring!
Jiang Yuan couldn't help but write this in again.
The monitoring of the cinema projection hall is quite important. It is unlikely to be broken for a long time. The probability of it happening to be broken when Bai Yuequn is watching a movie is very low. It is worth checking.
After writing this down, Jiang Yuan's confidence came back and he said: "I think we can start from the bloody clothes, send a police dog over, and search in Bai Yuequn's bar."
Huang Qiangmin said: "The smell there is too strong. Besides, Liu Jinghui has given the big and strong tunes, so it's better to use someone else."
"That's two lines, look for the murder weapon and bloody clothes, and check the surveillance room of the theater screening room." Jiang Yuan summarized, and then asked: "Do you want to communicate with Captain Lei?"
"I'll have a chat with him. He should have come to his senses by now." Huang Qiangmin smiled and went to arrange the manpower.
Jiang Yuan looked at the notes in front of him and fell into deep thought.
