A lot of people think of a serial killer as a pure madman or some kind of inhuman villain.

But this statement is not accurate, serial killers do not put the words serial killer on their faces, and later studies have shown that there are some highly educated, moral, and even willing idealists in this group to show up for the truth they are seeking.

They are handsome, well-dressed, and elegant, and some of them have stable jobs and connections, and there are a variety of reasons why they end up being serial killers.

The FBI defines a serial killer as murdering at least three people with a "cooling-off period" during the crime, as distinguished from a mass killer who commits a massacre in the same place in a short period of time, or a killer frenzy who goes on a murder spree.

And Jack the Ripper is just a textbook serial killer.

He committed his crimes, fixed in the vicinity of Whitechapel, with a coherent pattern of behaviour that, according to Lestrade's description, occurred in three cases within half a month, with a gap of ten days between the first and second cases and a shortened interval of five days between the second and third cases.

You can see that the speed at which he kills is noticeably accelerating.

Whether it's a mission, entertainment, ideals, or simply seeing it as a cause and becoming a serial killer, there's no doubt that they can get some satisfaction from the act of killing.

It's like someone who is addicted to games or big swords, but a serial killer is obsessed with killing.

After each Great Sword, the average person will have what is called a sage time, and the "cooldown period" is like the sage time of a serial killer.

Serial killers will use a murder experience to bring their excitement to a peak, after which their emotions will gradually regress, reminisce about their previous experiences, summarize their experiences, and keep learning until the next crime.

This is also where the trouble lies, because you're dealing with an opponent who is constantly evolving, and the shortening of the cooldown period shows that the emotional stimulation of murder is gradually waning, which is why he needs to commit crimes more often to be satisfied.

If Zhang Heng remembers correctly, on the third day after the first letter, there were two more murders in the Eastern District, but one of them had a different modus operandi, and later researchers generally believed that the case was not committed by Jack the Ripper himself, but it is not clear whether it was the work of an imitator, or someone fished in troubled waters and blamed Jack the Ripper after killing people in chaos.

In short, there is not much time left for Zhang Heng, and if it is possible, Zhang Heng does not want any more victims to appear, so the best result is to find the murderer within three days, of course, considering that the murderer's crime time is much faster than in history, he may not have three days available, and in addition to this, he also needs to race against Sherlock Holmes.

Zhang Heng did not waste time, after examining the body in the morgue, he immediately rushed to the scene of the crime, but the incident had been cleaned up for so long, and the suspected evidence had been put away by the police, and there were still some residual blood stains on the ground, but there were not many clues that could be collected in addition, but it could be seen from running through three places that the location chosen by the murderer was becoming more and more bold.

From the initial dark alley, to the stockyard area, to the fence behind the apartment, the likelihood of being spotted is increasing from floor to floor.

Zhang Heng marked the three crime locations on the map, and then he went to visit the person who first found the body and the last person to see the victim according to the address provided by the short police officer, these people have obviously been harassed by reporters and police and all kinds of idlers who inquire about the news for a long time, Zhang Heng just said it and looked very impatient.

However, when the latter took out the gold coins from his pockets, they all became hospitable again, and they repeated the words that they had repeated many times these days.

Zhang Heng had already seen this information from the report provided by the police, so this was not the focus of his attention.

Thanks to the blessings of those ripper lovers in later generations, Zhang Heng already has a list of suspects in his hands, and the specific names and ages may not be useful, but the corresponding occupations and motives for committing the crime are very valuable for reference.

For example, a retired sergeant later believed that Jack the Ripper was a seaman on a German merchant ship, because the Whitechapel district was close to the docks, and the time when the merchant ship came and left London coincided with the time when the victim was killed, so he speculated that the murderer was probably a seaman, and that he mysteriously disappeared and did not commit another crime because he went to the United States on that ship.

Zhang Heng could ask the seafarer if there were sailors near the person who last saw the victim on the night of the incident.

In addition, there are similar royal conspiracy theories, barber theories, midwifery theories...... This belongs to the wisdom of the people, and each theory has a corresponding entry point, but the effect is not very ideal after a circle, and the eyewitnesses have said everything, and they have not formed a unified enough caliber.

Zhang Heng realized that he might have taken a fork in the road, of course, since he had such an advantage in hand, he had to give it a try.

I haven't been busy all the way until I have lunch, and the sun is about to go down in a blink of an eye, Zhang Heng didn't continue, he has run a lot of places this day, and the information he got is also varied, it's time to stop and sort out his thoughts.

Zhang Heng returned to 221B Baker Street and saw that Holmes had finished dinner and was dealing with a plate of dessert.

He still looked unhurried, and when he saw Zhang Heng coming back, he raised his head and said, "How was your harvest today?" ”

"I don't have a clue yet, how about you?"

"I've found a very useful clue, and I'm digging deeper into it, and there should be results tomorrow." Sherlock Holmes laughed, "Do you need me to share some tips with you, my dear friend of the East?" ”

Zhang Heng shook his head, "Those who run early do not necessarily reach the finish line first. ”

"That's a good thing, but the one who runs early always has an advantage, and I'm already picking which opera to watch when the time comes." Holmes said, seeing Zhang Heng sitting opposite him.

Mrs. Hudson brought out the rest of the dinner in the kitchen, which was smoked meat, peas and bread, and a few cloves of fruit, and the dessert was pudding, Zhang Heng quickly finished it, wiped his mouth and returned to the bedroom, and took out the revolver he had bought three months ago, in addition to a kerosene lamp and a knife.

Sherlock Holmes raised his eyebrows, a little surprised, "You're going back?" ”

Zhang Heng snorted, "That guy may commit crimes in the near future, and even if I can't meet him, I can still investigate the environment and situation at night at the previous crime sites," after a pause, he added, "By the way, I also know about the group of maids." ”

"Yes," Holmes praised, "you're getting more and more integrated into the city. ”

Derpy said

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