"The growth period of Xiaopengcao is about 6 months. In late March every year, the leaves and stems are tender and the stems are 2~4cm long. In early April, the stems are 5~10cm long. After that, they enter the growth period and grow rapidly."

What he memorized was data from a certain place in China, so there would definitely be errors when copied.

But now it is enough to have a rough time range, and it doesn't matter if the error is larger.

The climate change in this mountainous area in the past month happens to be similar to the wild climate in March and April every year in a place in China that is the source of Lin Xinyi's data.

So Lin Xinyi copied the data and used it:

"The length of the dead grass that was pulled out stayed at 4.5cm."

"The living grass growing normally next to it has now grown to 10cm."

"Based on the growth habits of the little fluffy grass, it's not difficult to judge..."

"The time when these grasses were uprooted from the soil should have been 10 days ago or within 20 days."

It takes 10 to 20 days for the grass blades to be cut off.

The approximate time of death of the deceased is between 10 and 18 days.

The two time periods coincidentally coincide with each other.

And since the blades of grass were pulled out at least 10 days ago, it couldn't have been pulled out by those hikers or the Gunma Prefecture police who just arrived here a few days ago.

"The person most likely to sit here and rest, pulling out these grass stems out of boredom, is the murderer or the deceased!"

Lin Xinyi gave his own conclusion.

But Officer Fangtani still hesitated:

"Although the officers of the Gunma Prefectural Police and the hikers who discovered the body are excluded."

"But this does not completely prove that these blades of grass were pulled out by the murderer and the deceased."

"What if another group of hikers came here before the incident and sat here to rest?"

"It's very unlikely."

"After all...this forest is not close to the mountain road, so even hikers may not come here."

"It is already a very small probability event for a group of hikers to accidentally break in and find a body."

"It would be too much of a coincidence to say that another group of hikers had been here before the incident."

Lin Xinyi knew that even if the possibility mentioned by Officer Shiang Gu was low, it was indeed a possibility.

This possibility cannot be ruled out.

"But we don't need to rule it out."

Lin Xinyi smiled:

"All we need to know is that the murderer or the deceased might have been sitting here, resting and waiting, and pulling weeds impatiently."

"With this guess and this possibility, we have the direction for the next step of investigation."

"Oh?" Officer Fang Gu was a little confused:

I know that one of the murderers or the dead may have been sitting here waiting.

At most, this seems to barely confirm that the murderer and the deceased did not come here at the same time, and proves Lin Xinyi's previous guess that "the murderer and the deceased made an appointment in advance to meet here", right?

But even if these speculations are true, so what?

Would knowing that some of them had rested here and that they had arranged to meet here in advance really help solve the case?

How can we help the police find the identity of the murderer and the deceased among the vast crowd?

Officer Fangtani was a little puzzled.

He cast curious and expectant eyes on Lin Xinyi.

Lin Xinyi did not answer directly.

He just took out his mobile phone and smiled mysteriously:

"Officer Fangtani, wait."

"I'll send a text message and ask my friend to check it for me."

"If we are lucky enough, this case may be solved soon."

Officer Fang Gu: "???"

With the few clues they have, they don't even have a clue about the identities of the deceased and the murderer...

How could this case be solved directly?

Even in his mind, he couldn't help but feel a little confused.

But Lin Xinyi knew that this was not because Officer Jianggu was not quick-witted, but because he lacked criminal investigation experience in this area.

This experience is the experience of using information and communication technology to solve crimes.

To put it simply, it is to check the mobile phone number.

According to Lin Xinyi’s conjecture and deduction:

Since the murderer and the deceased had made an appointment to meet in this wilderness, in order to keep in touch, it was impossible for them not to bring their mobile phones.

And if they brought their mobile phones, one of them would arrive early and sit on the rocks waiting, so bored that he would pull grass to pass the time...

Then the person who arrived first was impatient to wait. Wouldn't he take out his mobile phone and call to ask when the other party would arrive for the appointment?

And if the murderer and the deceased called each other on this mountain, then...

"Noah's Ark."

"Can you help me check all the call records of the local telecommunications company in the past 10 to 20 days?"

"The address is XX Village near Haruna Mountain in Gunma County, the forest outside the village."

"There is a signal base station in this mountainous area."

"I want you to check whether any of the call parties dialed through this base station in the past 10 to 18 days has been registered as 'missing' in the police system recently."

Lin Xin sent his question to the artificial intelligence assistant via text message.

Noah’s Ark responded quickly:

"sure."

"I can help you check all call records that were relayed through the local signal base station within 10 to 18 days."

As long as the mobile phone card is activated, the mobile phone will usually automatically connect to the base station closest to it with the best signal.

As long as someone makes a call here, the corresponding dialing record will be left on the local base station.

As long as you retrieve the call record data of the telecommunications company, you can know who made calls to whom at a certain base station in a certain area during a certain period of time through this base station.

The principle is actually very simple.

It's not technically difficult either.

But the reason why Officer Furitani and Bermodichi didn't think of this at this time is...

In this era of underdeveloped communications, and even in the future of advanced technology, very few people solve crimes in this way.

Because in densely populated areas such as cities and rural areas, a base station may record tens of thousands of incoming and outgoing calls every day.

The base station can only record the dialed number, but cannot record the content of the call. It is simply impossible to find the call that the murderer made from so many dialing records.

Because of this, this "stupid method" of confirming the murderer's phone number by checking the massive dialing records of the base station rarely has the opportunity to appear in any era.

Officer Furitani and Belmod have never seen this method of solving crimes before.

That's why they can't figure out these joints.

However, Lin Xinyi had studied many classic cases during his work and knew that in sparsely populated rural areas, he could try this method of checking base station dialing records to confirm the phone number of the person involved.

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

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

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

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

The only people who make calls through this base station in the mountains are usually hunters and climbers looking for excitement.

There are not many people who come to the mountains for excitement, and it may take ten days and a half for a group of people to arrive.

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

Think about it, not many people have made phone calls in this deep mountain within 10 to 18 days.

really...

Noah's Ark quickly gave the search results:

"Mr. Lin, I found it:"

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