Chapter 219: Two Lines

Sitting in the office of the Qianjin District Criminal Police Brigade, Jiang Yuan carefully compared Bai Bai Yuequn's footprint rubbings with the bloody footprints at the crime scene, repeatedly verifying them.

That is the bad thing about footprints; they cannot identify a suspect one-to-one. They can approach infinitely, but they cannot be confirmed.

Otherwise, if it were like fingerprints, it could be used directly as ironclad evidence for prosecution.

Barefoot prints can be treated like fingerprints, but unfortunately, most of the time, they don't exist.

Killers generally don't kill barefoot.

Although it cannot be 100% confirmed, from Jiang Yuan's perspective, this degree of overlap basically confirms Bai Bai Yuequn's identity as a suspect.

If it has approached this level and he is still not the killer, then this just adds another layer of coincidence.

Considering that the third son, Yuan Yuan Yutang, was only in his twenties, a "diamond pestle" couldn't have made many lovers and rivals, and a mouth that could "break legs" meant the people he offended should be limited. So, from a probability perspective, how low is the probability of having a motive for murder and also having similar footprints?

Therefore, when Lei Xin, the captain of the Qianjin District Criminal Police Brigade, said there was an alibi witness, Jiang Yuan questioned the witness immediately.

It is difficult for physical evidence to lie, but it is too easy for witnesses to lie.

However, this was also the first time he had encountered such a situation, and he had some doubts himself.

What if?

Just as Jiang Yuan was frowning and studying the footprints, Huang Huang Qiangmin walked over with a smile.

"Can't figure it out?" Huang Huang Qiangmin looked at Jiang Yuan.

"It's not that I can't figure it out, but..." Jiang Yuan didn't know how to express it to Huang Huang Qiangmin.

"I don't understand technology, and I understand footprints even less. However, looking at what you mean, Bai Bai Yuequn's footprints are very consistent with the footprints at the scene?" Huang Huang Qiangmin asked.

"Yes." Jiang Yuan was full of words and said continuously: "The height is consistent, wearing height-increasing shoes is also consistent, the shoe size is also consistent, wearing large shoes is also consistent; there is also weight, age; I also looked at the surveillance video, his stride and gait are basically consistent. If it were a stranger..."

Huang Huang Qiangmin smiled and pressed down on Jiang Yuan's waving arm, whispering: "No need for 'if', it is him."

"Ah?" Jiang Yuan was a bit surprised. To be honest, he didn't dare to be so certain.

"You were the one who told me about the CSI effect before; I think you have a bit of it now." Huang Huang Qiangmin smiled and said: "Must there be DNA and fingerprints to identify the killer? Must there be 100% certainty to prosecute? If it were like that, how did we handle cases 20 years ago?"

Jiang Yuan said: "So you relied on confessions back then?"

"Confessions aren't 100% either, and coerced confessions aren't the patent of Americans." Huang Huang Qiangmin waved his hand and said: "There are already enough clues."

"Then Captain Lei..."

"He just came into contact with the case and doesn't know much about it yet. Moreover, the case happened in his jurisdiction, so he must consider more. Don't worry about him for now."

"Then..."

Huang Huang Qiangmin said: "Don't stare at the footprints anymore."

"Then what should I look at?"

Huang Huang Qiangmin said: "Anything is fine. We have a saying in criminal investigation: 'Isolated evidence cannot stand.' In my interpretation, that means when a case is solved, there is definitely more than one piece of evidence. Now, we have actually finished the hardest part, which is identifying the killer; now we need to prove this."

Huang Huang Qiangmin counted on his fingers and continued: "Assuming the person was killed by Bai Bai Yuequn, let's assume his alibi is fake. The key is, can we prove it? Can we lock him down with physical evidence?"

Jiang Yuan immediately pulled himself out of the dead end.

Indeed, the killer of this case left a lot of evidence. As long as this evidence can be linked to Bai Bai Yuequn, the case is solved.

Assuming someone is the killer and then proving they are the killer is also the most commonly used method in criminal investigation.

In fact, most cases are like this. Still the same saying: experienced criminal police can pick out a first-time killer with a glance.

Therefore, burglary is often harder to solve than home invasion murder—burglary that is easy to solve is usually due to the suspect not being serious and not being well-prepared. Some professional thieves, having not been caught for too long, are prone to paralysis and negligence, and coupled with high business intensity, they are prone to making mistakes.

The Hangzhou wife-killing case, and many other wife-killing and husband-killing cases, are similar situations.

Most of the police's time and energy is used for argumentation.

The Yuan Yuan Yutang murder case is not complicated to talk about.

Assuming Bai Bai Yuequn is the killer, he just did some things to set up a smokescreen.

He changed into shoes he didn't usually wear, didn't get injured at the scene, and had an alibi, but doing these things itself actually involved a lot of work.

And the more he did, the easier it was to make mistakes.

The easier it was to lock down evidence.

Jiang Yuan couldn't help but recall the autopsy scene from a few hours ago.

Yuan Yuan Yutang and his former/current 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, the edge was sharp, and the most powerful thing was that after a total of more than 30 stabs, the sharpness of the dagger did not decrease.

Such good quality would be an absolute divine weapon in ancient times, and even in modern times, it would have to be an expensive military dagger.

And in the domestic environment, such daggers are easy to buy if you say they are easy, and hard if you say they are hard, and it is still relatively easy to leave traces.

Murder weapon: military dagger.

Jiang Yuan wrote these two words in his notebook and underlined them.

Huang Huang Qiangmin nodded and didn't say anything.

He also saw the autopsy report. The military dagger also explained why the killer killed two people with one, stabbing dozens of times without getting injured himself.

Many novice murderers might not have even killed a chicken before killing, at least they haven't slaughtered medium-to-large mammals, so they don't know how much resistance human muscle tissue has.

Things like daggers or short knives are completely different from spears and broadswords.

The reaction force of a dagger or short knife is greater, and when the technique is wrong, the wrist and the web between the thumb and index finger have to bear huge pressure.

If you give a novice a broadsword or spear to practice for a while, the novice can also gather the strength of the whole body to swing, stab, and poke. Daggers or short knives won't work, and civilian products won't be as sharp after a few stabs, and if you use too much force, you are likely to hurt yourself.

In addition, killing is still a very tiring thing.

To be more precise, stabbing someone with a knife is very tiring.

It's like slaughtering a pig in the village; it takes several big men to hold it down and tie it up, and it will still struggle.

One stab, two stabs, three stabs are fine, but thirty-plus stabs are not so easy. The movements behind become deformed, and the probability of mistakes or hurting yourself increases.

The sharpness of a military dagger can partially solve this problem.

Coupled with the calluses on Bai Bai Yuequn's hands, the obvious look of having practiced... Jiang Yuan even suspected that he was prepared.

Key!

Jiang Yuan wrote these two words in his notebook again and underlined them again.

Yuan Yuan Yutang's door lock was not damaged, and there were no traces of technical unlocking, so the killer opened the door with a key, took advantage of Yuan Yuan Yutang and his boyfriend being asleep, stabbed his boyfriend to death first, and then stabbed Yuan Yuan Yutang multiple times, causing his death.

This is also one of the reasons why the suspect list is mainly based on lover and rival relationships.

No matter how many work contacts Yuan Yuan Yutang has, they cannot get the keys to his home.

Only lovers or rivals are easier to get keys made.

Bloody clothes.

Jiang Yuan immediately thought of the killer's murder process.

The killer's subsequent handling of the crime scene was relatively rough. Perhaps because he was in a hurry, he didn't care about the bloody footprints at all, and the way to eliminate traces was to splash a basin of water.

But with that amount of bleeding at the scene, the killer's clothes must have been covered in blood. He could take a shower and change clothes in the bathroom, but it is very difficult to clean the changed clothes in one day.

Ordinary people either throw them away, burn them, or bury them.

But no matter which one, it takes time.

Bai Bai Yuequn still lived in the city center, where there is plenty of surveillance.

Therefore, the places where he could place the bloody clothes were very limited; perhaps in the bar or office.

Cinema screening room surveillance!

Jiang Yuan couldn't help but write this down again.

The surveillance in the cinema screening room is relatively important. It is impossible for it to be broken for a long time, and it just happened to be broken during the time Bai Bai Yuequn was watching the movie; the probability is very low, and it is worth checking.

After writing this down, Jiang Yuan's confidence returned, and he said: "I think we can start by looking for the bloody clothes, call a police dog over, and search in Bai Bai Yuequn's bar."

Huang Huang Qiangmin said: "The smell there is too strong, and Dazhuang has been transferred to Liu Liu Jinghui, so let's use people."

"That is two lines: find the murder weapon and bloody clothes, and check the cinema screening room surveillance." Jiang Yuan summarized, and then asked: "Do you want to communicate with Captain Lei?"

"I'll talk to him; by now, he should have come to his senses." Huang Huang Qiangmin smiled and went to arrange manpower himself.

Jiang Yuan looked at the notebook in front of him and fell into deep thought. ===== CHAPTER 220 =====