Coroner Coroner

Because in the sparsely populated countryside, a base station with a signal coverage of several kilometers may add up to only a few phone numbers dialed in and out every day.

It is naturally not difficult to find the person you want to find from a few call records.

But now, it is not only in the countryside, but also in the mountains.

According to the owner of the homestay, within a few kilometers after entering the mountain, there is only one signal base station.

People who can make calls through this base station in the deep mountains are generally only hunters and climbers who come here looking for excitement.

There are not many tourists who dare to venture into the deep mountains, and it may take ten days and a half months to come to such a team.

Coupled with the approximate death time range given by Lin Xinyi, the scope of investigation was narrowed down to within 10 to 18 days.

Within 10 to 18 days, there are not many people who have made phone calls in this deep mountain.

Sure enough... Noah's Ark quickly gave the search results:

"Mr. Lin, I found it:"

"In the past 10 to 18 days, there was only one dialing record made through the signal base station you mentioned."

“时间是在距今13天前，下午1点13分31秒，至1点15分07秒。”

"The number was dialed from the 'Deep Mountain Base Station' you mentioned."

"And the base station where the receiver of the call is located is also this base station."

"Only one?" Lin Xinyi responded by typing quickly on the keyboard with some surprise: "And the person who answered the phone was also within the signal coverage of this base station at that time?"

This means that the two people who made the call and answered the phone were both on this mountain at the time, not far apart.

This is exactly in line with what Lin Xinyi deduced before, "the murderer and the deceased made an appointment here, and the first arrival waited for a long time to call the other party to inquire".

Based on this alone, it can be basically confirmed that the call was made between the murderer and the deceased.

But this still needs to be proved——

The most direct way to prove it is:

"Noah's Ark."

"Have you found out who was registered as 'missing' in the police system?"

The deceased had passed away quietly for more than ten days.

In the past ten days of her "disappearance", her relatives and friends may have reported the case to the local police nearby, making her registered as a "missing person" in the police system.

Just compare the identity information of the owner of the mobile phone number with the national missing person records to see if there are any matching identities...

It can be proved whether the two people who were on the phone in this mountain at that time were the deceased and the murderer in this case.

And the identity of the deceased and the identity of the murderer can be easily determined accordingly.

This is technically not difficult.

For the artificial intelligence Noah's Ark, which can be called an alien creation, this should be a piece of cake.

But what Lin Xinyi didn't expect was...

"Feel sorry."

Noah's Ark gave a negative answer:

"The mobile phone numbers of both parties to the call have not been registered with their real names."

Lin Xinyi forgot.In this day and age, real-name registration is not required at all to open a mobile phone number.

If you want to find out the identity of the owner from the mobile phone number, you have to spend some extra effort.

And most importantly...

"You are also mistaken."

There is helplessness between the lines of Noah's Ark:

"As far as I know, your country has never built a nationally networked police data system."

"Including the Tokyo Metropolitan Police Department, many places are still recording data with paper files."

"What you call a 'missing persons database' doesn't exist."

"However, in the name of the Tokyo Metropolitan Police Department, I can help you send an investigation email to local police stations across the country, asking them to fax their missing persons files."

"Of course, these paper materials..." Noah's Ark added disgustingly: "You have to read it yourself."

Lin Xinyi: "..."

"Okay..." Lin Xinyi finally realized that he was excited for a moment, and his spirit "traversed back".

Noah's Ark may be science fiction, but this era is still behind.

This artificial intelligence was born a little earlier.

Otherwise, it will become Skynet in minutes, and it will not be a problem to control the world.

Now Noah's Ark can't help, and Japan doesn't have a nationwide missing persons database... So what should we do?

Really go through those faxed paper documents?

When will it be turned over?

Just thinking about the sea of ​​paper in that book, Lin Xin's scalp felt numb.

"Noah's Ark, is there no other way?"

"Yes." The artificial intelligence replied: "I can help you try to retrieve the text message records of these two numbers, and through intelligent analysis of the content of the text message conversation, try to confirm the identity of the two mobile phone number owners."

"But it will take some time."

"And besides that..."

Noah's Ark quickly gave another solution to the disgust:

"I can also help you locate those two mobile phone numbers and determine the approximate location of the owner."

Mobile phones don't have GPS these days.

But Lin Xinyi knew that the mobile phone positioning mentioned by Noah's Ark should refer to the base station positioning method that existed in this era:

Usually, in a city, a mobile phone will be under the signal coverage of multiple base stations.

The mobile phone will "measure" the downlink pilot signals of different base stations, and obtain the signal TOA (time of arrival) or TDOA (time difference of arrival) of each base station.

According to this measurement result, combined with the coordinates of the base station, the coordinate value of the mobile phone can be calculated.

The error of this positioning method is generally more than 100 meters.

Moreover, the fewer base stations in the target area, the greater the error.

If it is in a sparsely populated mountainous area with only one signal base station within a few kilometers, the error can be as large as several kilometers.

This method of mobile phone positioning is definitely not too accurate.

But if you can know the approximate location of the murderer through mobile phone positioning, it will be more or less helpful to the detection of the case.

So Lin Xinyi waited with great anticipation for Noah's Ark's response.

Not long after, Noah's Ark sent him another text message:

"Among the two mobile phone numbers that were called in the mountains that day:"

"Mobile phone number xxxxxxxx, has been turned off, no signal."

"Records show that it was last connected to the Internet 13 days ago at 3:32:18 pm."

"This..." Lin Xinyi realized something:

The afternoon of 13 days ago was when that call happened.

And one of the two parties in the call at that time has been shut down since that afternoon.

"This is probably the cell phone of the deceased!"

"After killing her, the murderer must have taken her mobile phone away from the scene and disposed of it."

Lin Xinyi was even more certain that the two parties in this phone call were the murderer and the deceased in this case!

"What about the second phone number?"

"This should be the murderer's phone number—"

"Where is the murderer now?"

Noah's Ark quickly sent a reply:

"The second mobile phone number is currently activated, and the base station connected to the mobile phone number..."

"Mr. Lin, this is the base station you are using now."

"What?!" Lin Xinyi was surprised:

The murderer's mobile phone is now using the same signal base station as him?

Isn't this saying...

"Yes."

Noah's Ark sent a conclusion directly through text messages:

"The murderer you are looking for is now on this mountain."

Chapter 536

The murderer's mobile phone signal was located here.

But because it is located deep in the mountains, there is only one base station within a few kilometers.

Therefore, the positioning error is also several kilometers, and it is impossible to know the specific location of the murderer at this time.

The only thing that is certain is that he is now in this deep mountain.

How to find him?

Lin Xinyi fell into deep thought quietly.