Now the west side of this location is Octagonal Well Street, but on the east side is a barren mound, and thirty meters apart is the bell lane that Yu Cheng said.

According to Ning Zhiheng's inference, before the Intelligence Bureau was preparing to carry out a large-scale search, Yan Yichun knew that the carrier pigeon was about to be arrested, so he quickly notified the news to the Special High School Headquarters, so that the Japanese knew about this operation, and urgently activated the alarm device, that is, Takano Yuta and his wife.

Takano came here as quickly as possible, and carved a clear triangle on the east side of this cypress tree as requested, which was a warning signal that had been agreed on a long time ago.

When the carrier pigeon saw this signal, he immediately realized that he was about to be exposed, transferred the radio station in time, and was ready to deal with the search, so that the intelligence department searched and arrested, and finally found nothing, so that the carrier pigeon escaped this crisis.

When Ning Zhiheng interrogated Takano Yuta before, he didn't notice the special location of this signal, but simply thought that this mark was for the target to see when he passed by the street, but now he understands that the other party doesn't need to go out of the house at all, he only needs to use a telescope to see this mark clearly in the residence in Bell Lane, and even if he has good eyesight, he can see it without a telescope at all.

Then you can go to Bell Lane to take a look at this location now, and from which house can clearly see the cypress tree next to Ning Zhiheng, then its occupants may be carrier pigeons.

Because the radio signal has been transferred, then check whether the occupants of these houses have moved out, so that the target of suspicion can be greatly narrowed from 58 households to a few or even fewer, so that the investigation will be twice the result with half the effort!

Ning Zhiheng and his team members rushed to the mouth of Bell Alley, and not long after, a sergeant from the police station who received the notice also hurried over with the security police.

I saw Ning Zhiheng and his party from a distance, and they ran over quickly.

Running in front of him, the sheriff hurriedly stood up and saluted, panting and said, "Sir, we are ordered to come to cooperate with your investigation, and everything is subject to your instructions. ”

Ning Zhiheng nodded and ordered, "You only need to take us to Bell Alley and check on a few households, understand?" ”

"Yes, I understand!"

The sheriff hurriedly led the way in front and led Ning Zhiheng and his party into Bell Alley, a long and narrow alleyway with many residents crowded on both sides.

Ning Zhiheng pointed to the residents on the west side and said, "Only check the west side, and immediately check from house to house!" ”

Because only the residents on the west side could see the cypress tree, Ning Zhiheng ordered, and the police hurriedly knocked on the doors of the residents on the west side one by one in order, and let Ning Zhiheng and them enter for inspection.

When these residents saw that a group of soldiers and police officers had come to the door, they were so frightened that they did not dare to say anything and hid far away.

After Ning Zhiheng entered the room, he just came to the window on the west side to check if he could clearly see the location of the cypress tree, and soon he found that the pile of wasteland in front of the cypress tree blocked the view, and the residents on the first floor could not see the location of the cypress tree, or could only see part of the trunk, and could not see the triangle he had just carved at all.

He immediately called the sheriff behind him and asked, "How long has this loess mound been here?" ”

The sheriff touched his head, and for some reason, replied truthfully: "It's been many years, and no one has taken care of it." ”

In other words, in June last year, this mound of wasteland existed, so for the residents on the first floor, there was no warning signal.

So Ning Zhiheng specially looked for a house with a two-story building, and sure enough, the houses on high ground could clearly see the triangular signal on the cypress trees.

There were not many such houses, only four families, and soon the residents of these four families were brought to Ning Zhiheng.

Ning Zhiheng slowed down his tone as much as possible, and asked with a pleasant face: "Don't worry, everyone, we are just a general investigation, and we will not have malicious intentions towards you, when did you all move in, tell me the specific time." ”

Seeing Ning Zhiheng speak politely, the nervousness of these residents eased, these uniformed people were most afraid of these people in uniform these years, once they got into trouble, it would be a big trouble for these civilians.

As a result of the inquiry, three of the four families were old residents, and only one family had just moved in in August last year.

This is the house! Ning Zhiheng thought to himself in his heart, the carrier pigeon had escaped the search, knowing that Bell Lane was already very unsafe, and he would definitely arrange to get out and evacuate, moved to the vicinity of Black Corridor Street, and now appeared in the paint shop again.

He kept moving his hiding place, which brought certain difficulties to the detection of this case, but in Ning Zhiheng's eyes, it was difficult to hide his whereabouts, revealing clues.

He then asked, "Do you know who the previous occupants of this house were?" Bring his landlord and neighbors to me. ”

After a while, a thin old man was brought to him, and he said tremblingly: "The previous tenant of this house, surnamed Huang, is called Huang Zhongxin, in his thirties, who has rented a house with me for two years, moved out at the end of July last year, and only moved in in August. ”

"Do you know where Huang Zhongxin moved?" Ning Zhiheng asked, he also knew that there was little hope, but he still confirmed.

As a result, the old landlord shook his head and replied: "I don't know this, he and I are not familiar with each other, except for saying a few words when paying the rent, and nodding when we usually meet, and will not say anything more to me." ”

I asked a few neighbors again, and the answers were all about the same, I usually don't have a deep relationship, and I don't know this Huang Zhongxin very well, but I know that he seems to be a company employee, with a good salary, and rented the largest house on the second floor.

Just a month after that late-night search, Mr. Huang moved out and has not been seen since.

According to the old method, Ning Zhiheng gathered all the neighbors who had seen Huang Zhongxin together, took out a pen and paper, and began to sketch the portrait of Huang Zhongxin according to their description.

The more people described, the more accurate the portrait became, and it took nearly two hours for Huang Zhongxin's portrait to finally be completed.

After two hours of brief contact, the surrounding neighbors had cleared their guard, and they all nodded their heads at the portrait, agreeing that it was almost no different from a real person.

It seems that this portrait is very successful, according to it, Ning Zhiheng can initially grasp the most direct clues, greatly saving many unnecessary links, and it is only a matter of time to find Huang Zhongxin.

Ning Zhiheng returned to his office and immediately picked up the phone and dialed the telecommunications department.

The telecommunications department received a call from Ning Zhiheng, and someone rushed over immediately.

There was a knock on the door, Ning Zhiheng said and came in, and it was Bian Deshou, the major leader of the telecommunications department, who pushed the door in.

I haven't seen him for a few months, but Bian Deshou's face is much more ruddy, and now the status of the telecommunications section in the military intelligence investigation department has also been greatly improved, many advanced instruments have also been purchased, and the number of personnel and equipment has been doubled.

Bian Deshou's life is getting better and better now, of course, when he heard Ning Zhiheng's call, he still rushed over as soon as possible.

"Team Leader Bian, I'm really sorry, I have to trouble you to come here." Ning Zhiheng got up to greet him, invited Bian Deshou to sit down on the sofa, and then put the monitoring record in front of him.

"There, Team Leader Ning's order is to come over no matter how busy you are. How? Is it a matter of listening to records? Bian Deshou said with a smile.

Ning Zhiheng nodded and said: "There are some questions, you know, I don't know much about this aspect, and I ask Team Leader Bian to solve my doubts!" ”

Bian Deshou agreed repeatedly: "You must know everything, and you must say everything!" ”

Ning Zhiheng pointed to the listening record and said: "There is an airwave signal that we have been in contact with before, and the intelligence department almost caught someone, but it fell short and let him escape."

Now that the listening log shows that it reappeared near the paint shop seven days ago, I wonder if we can find a more specific location for the next time he appears? ”

Bian Deshou brought over the monitoring record, and the content on it was what he was responsible for monitoring, and the situation was very clear.

Hearing Ning Zhiheng's words, he couldn't help but smile bitterly, and said to Ning Zhiheng: "Team Leader Ning, what you said is really difficult for us to do. ”

He sat up straight and carefully explained to Ning Zhiheng: "Although our technical ability has been greatly improved, we still can't specify the radio wave signal to the precise location, and there are too many radio stations in Nanjing, the radio waves are complicated, our equipment can't quickly search and locate a certain signal, unless we know the approximate location and time of his upcoming appearance, move the equipment to a close location, and wait for it to appear, this distance is not too far, otherwise it is difficult to determine."

In April last year, Team Leader Yu of the Intelligence Section did just that, we spent a lot of effort to transfer the equipment, and it took another two months to gradually eliminate other radio interference, lock it down, and figure out its transmission pattern."

Ning Zhiheng knew that his request was a bit excessive as soon as he heard it, and asked again: "This radio wave has appeared on the Black Corridor Street before, is there any record of its monitoring, has the frequency of its transmission changed, or once every ten days?" ”

Bian Deshou spread his hands and said helplessly: "After the appearance of the Black Corridor Street, its frequency of reporting has changed greatly, and the time it sends is too short, we have not mastered the law of reporting, and we cannot guarantee the possibility of missing reports, after all, we need to monitor too many radio stations, you probably don't know, just to operate a set of monitoring equipment, at least a dozen to twenty telecommunications personnel are needed, our work is already very heavy, and the limitations of manpower and equipment make us unable to do so precise." ”