Lao Liang was stunned and quickly picked it up and found that it was a neatly folded yellowed note. "What is this?!"

After opening the note, Xie Xingyin felt that the rough paper seemed a bit familiar. He took out Keiko's diary and compared it, and found that it was indeed the same paper.

"Who tore this off?" Lao Liang's eyes widened.

It is obvious that Jia Ming secretly tore out a page of Keiko's diary without leaving any trace.

"This idiot!" Lao Liang said angrily, "No wonder we can't find anything useful!"

Xie Xingyin frowned without leaving any trace. Jia Ming had gone upstairs a long time ago. He just took away the key information without saying a word, but he left a notebook to confuse people. It was quite unkind.

"Come on, come on, what's written on that paper? Read it for me?" Lao Liang poked his head curiously.

However, Xie Xingyin spread the piece of paper in front of him and saw a line of letters written on it:

ullcoznnkxnkgj

These letters don't look like they can form meaningful words.

Xie Xingyin frowned: "garbled code?"

"Ah, garbled characters? No way? Thanks, brother, don't you understand foreign languages?" Lao Liang scratched his head and turned around to call Xiao Yan, "Hey, what about that? Little girls, you have to learn foreign languages ​​in high school, right? You can understand it?"

?"

Xiaoyan also timidly shook his head: "I don't understand this."

Xie Xingyin looked at the messy string of letters and shook his head: "It must be gibberish, or it could be an alien language."

"Hey, that's weird." Lao Liang scratched his head and said, "It's really just a line of letters with no meaning? Then why did grandson Jia Ming tear it off..."

Xie Xingyin said: “It’s not necessarily boring, it’s just that the content has been encrypted.”

"Encrypted?" Lao Liang grabbed the note and looked at it sideways and vertically, then gave up, "Lao Xie, can you decrypt it?"

Xie Xingyin frowned: "That's embarrassing, at least we have to know what type of password it is first."

"Does Jia Ming know? When Jia Ming comes back later, we will ambush him, capture him and torture him?" Lao Liang was still making bad ideas.

Xiao Lu didn't know when he stood in front and suddenly said: "Caesar."

When Xie Xingyin heard this, his eyes suddenly lit up.

Yes, Caesar cipher.

This piece of paper was torn out of Keiko's diary. When Keiko committed suicide, she held a coin with Caesar's head in her hand. This should be the hint that Keiko left for them.

The Caesar cipher is a very simple and effective encryption method. It is said that Caesar, the dictator of the ancient Roman Empire, used this method to encrypt important military information.

The encryption method is to follow the alphabetical order, offset the text to be encrypted by a fixed number, and then replace it with other letters as the password.

For example, when the offset is set to 3, the position of a in the alphabet three digits behind is d, then use d to replace a. Write a as d, b as e, c as f, and so on.

After listening to this, Lao Liang seemed confused and confused: "Then do you know what the offset is?"

The number of coins in Keiko's hand should represent the offset, but with such an old photo, no matter how wide your eyes are, you can't tell how many coins she has in her hand.

Isn’t that in vain? Lao Liang was a little discouraged.

"I really don't know." Xie Xingyin said, "But if it is really a Caesar cipher, you don't need to know the offset."

Most of Caesar's enemies on the battlefield were illiterate and regarded this encrypted information as a foreign language that they could not read. In fact, the security of this encryption method was very average, and people with a little knowledge of it could completely crack it with violence.

.

The offset of the alphabet is only 25 at most. Use the enumeration method to try one by one and find a meaningful combination to solve it.

Xie Xingyin grabbed the pen and started trying one by one.

1 is wrong. 2 is wrong.

3 is not right either...

When he tried 6, he finally had a decent line of letters on paper.

"It should be this one."

Lao Liang looked over and saw a line of letters written neatly on the paper.

offwithherhead

"I don't understand foreign language, what does this mean?" Lao Liang asked.

"The Red Queen's famous saying - cut off her head." Xie Xingyin lowered his eyes and stared at the yellowed paper.

"No, whose head are you trying to chop off? Is the human-faced dog Jia Ming or Li Wei?"

Lao Liang was still confused and was about to ask further questions when a short scream suddenly came from outside the door.

"ah--!"

The four of them turned around and rushed out to take a look, only to see Xiaoyan's two female classmates standing outside the elevator in fear, wondering what they had seen.

The unmanned elevator door slowly closed again. Xie Xingyin pushed aside the others and stepped forward, pressing the switch.

The elevator dinged and opened.

In the elevator, Jia Ming's pupils were gray and lifeless. He was still holding the house-holding talisman at the door of room 1404 in his hand. There were two bloody holes on his neck, as if something had bitten his throat.

Xie Xingyin looked stern: "Not good!"

He turned around and rushed out of another room, this time breaking in directly without knocking.

There was silence in Li Wei's room. The "patient" who should be lying in the room to rest was nowhere to be seen.

The light in the room was dim, and the curtains blocked the moonlight. Xie Xingyin walked to the window and opened the heavy curtains——

The wind blew in.

There is no security window. You can easily climb out through this window and jump to the platform outside.

Xie Xingyin was silent for a moment, then suddenly turned around and left.

Lao Liang saw that his expression was not good, so he quickly stopped him and said, "Wait a minute, are you sure it's Li Wei? How about we take a closer look?"

But Xie Xingyin said: "No need, I suddenly remembered that there is someone else we haven't asked."

"who?"

"Keiko."

When Lao Liang heard this, his jaw almost dropped: "What? That, that, that's a ghost!?"

But after thinking about it, it seems to make sense. The human-faced dog will not tell them. I am afraid only Keiko knows what happened in this apartment.

They found hints in Keiko's diary, but except for that page of passwords, all she left in her diary were invalid information, as if to hide it from others.

Keiko seems to be hiding from the human-faced dog too.

The other two girls stood in the distance, not knowing what was going on, watching vigilantly as they crashed into Li Wei's room and ran out one after another.

Xie Xingyin had no time to take care of them, so he took Lao Liang, Xiao Lu and Xiao Yan and headed straight to the 14th floor.

When they walked to door 1404, they found that the door was open, and the talisman paper posted on the door had indeed been taken off.

Lao Liang couldn't help but feel regretful, shook his head and sighed: "Alas..."

Jia Ming took advantage of the fact that he had already gone upstairs and was too smart to listen to their advice. He firmly believed that Xie Xingyin had some ulterior secret that he was hiding from him.

So Jia Ming ignored his advice and went upstairs alone when no one was around. Then an accident happened - his throat was bitten by the human-faced dog before he even had time to struggle.

This is not called cleverness but being misled by cleverness. This is called 24k pure stupidity.

"Oops." Xie Xingyin said, "Lao Liang, you said the talisman outside room 1404 is to suppress ghosts, right? The talisman was removed by Jia Ming, did the female ghost run out?"

Lao Liang slapped his thigh and quickly took out the compass. He turned left and right, then turned again, and turned around the whole room. The compass needle did not move.

"It's broken, it's broken, it's really running away." Lao Liang spat.

"This apartment is so big, where can we find her?" After going around and around, we returned to the original point of finding the needle in the haystack.

Really tricky.

Xie Xingyin walked around the apartment twice and stood at the door of the bathroom: "Actually, there is something I can't figure out. If Keiko is dead, where is the body?"

The bodies of other apartment residents are all in the room, why not Keiko’s?”

Lao Liang opened his mouth: "What do you mean?"

Xie Xingyin stared at the dark hole.

"That's where the female ghost comes from. I want to go in and have a look."

Hearing what he said, everyone else's hair stood on end. Xiao Yan crossed his arms and got goosebumps: "Don't, that might be her lair..."

"Wait a minute." Lao Liang took his compass and looked around to make sure the pointer was not moving at all, and calmed down.

"There's nothing in there for now. Thank you for going back quickly."

There is no other way now, they cannot let go of anything suspicious.

Xie Xingyin climbed in with a flashlight in hand and quickly found the upward passage.

The entrance to the passage was a bit narrow, and a skinny female ghost could barely get in and out, but Xie Xingyin, a grown man, couldn't climb up, so he had to use a flashlight to look up.
To be continued...