Li Yi returned to the team, Qin Gang was already sitting at his desk, and the security surveillance video was playing on the computer screen, and it seemed that he had come back early in the morning to start work.

"The early bird gets the worm." Li Yi said.

"I haven't eaten yet."

Qin Gang yawned, "I just watched the beginning, and somehow I fell asleep, if you don't come back, I should still be in a dream." ”

Li Yi looked at Qin Gang with disdain, "It's not okay to be so hot-blooded, I passed by Team Liu's office and glanced in, I wasn't there, I guess I went to the meeting, so I don't have to talk to him first." ”

Qin Gang also looked at Li Yi, "Did you not sleep well in a night of excitement and hung a panda eye." ”

Li Yi went to the bathroom and looked in the mirror, his eye circles seemed to be a little swollen, and there was nothing wrong with him.

The two of them rearranged the report of the technical team together, and supplemented the on-site information by the way, which Li Yi dictated and Qin Gang recorded on the computer.

A: The security guard started to patrol the building at 8 o'clock in the evening, and the time point when the thief sneaked into the rooftop was after the security patrol, and there were two possibilities for entering the rooftop, one is that the security guard left without locking the door after the inspection, and the other is to get the key from other means.

B: Obtaining the keys from other sources will change the nature of the case and the scope of persons involved in the case will be expanded, which is not supported by the available evidence.

C: There are 10 blood samples collected at the scene, but there are three different DNAs, one belongs to the victim and two are currently unknown, and it is inferred that one belongs to the suspect and the other belongs to an unknown third party at the scene. (Note: In Ms. Lin's transcript, there was only one suspect at the scene)

D: Footprints, divided into two types, one is the mark of the shoe on the ground, and the other is the trace of the bare foot on the wooden floor. The focus of evidence collection is in the bedroom, the sneaker prints are very obvious, and they do not belong to any pair of shoes at the scene, comparing the previous 4 case reports, the shoe prints belong to the same person, who is also the suspect in the Donghu case; Two slipper imprints, belonging to two pairs of slippers in the on-site bedroom; The two sets of footprints, collected at the foot of the bed in the bedroom, are very clear, in contrast to the messy shoe prints on the side of the bed at the scene. Two sets of footprints, inferred that in addition to the suspect, there are two other people in the bedroom, one of the footprints belongs to Ms. Lin, and Ms. Lin's record is the only one at home, her husband was indeed on a business trip at the time of the crime, so the other footprint will definitely not be Zhou Gong's, it belongs to a third party.

E: There are three different sets of data on slipper tissue residues, belonging to three individuals. Two pairs of slippers in the bedroom, in the fine tissue residue, three different sets of DNA were detected, one of which belonged to Ms. Lin, one was inferred to belong to Ms. Lin's husband, pending verification, and the last group was also unknown, and it was inferred that it belonged to a third party at the scene, which also needs to be verified.

F: The victim's wound is mainly caused by scratching, no stabbing and no chopping, so the wounds are relatively shallow and do not cause fatal injuries.

G: At the scene of the crime, there were no items lost, no loss of cash in the drawer of the TV cabinet in the living room, the furniture in the bedroom was neatly placed, there were no traces of collision, there were no traces of fierce struggle in observation and analysis, no alarm to any neighbors left and right, and it was inferred that the sound and noise were not loud.

H: Suspect, the surveillance video in the basement captured the time of escape, and the security surveillance video took a clear frontal photo, but Ms. Lin could not identify the photo. (Note: There is amnesia or lack of light at the scene resulting in blurred vision, and there is no clear memory of the suspect)

I: The distress call, this is the key point, the time point of the call is unreasonable, the dialing time is 4 minutes later than the time when the suspect escaped and disappeared in the security surveillance video, and the on-site running measurement and analysis, the actual time should be at least 10 minutes late.

J: There is a suspicious location of the call, Ms. Lin's record shows that the mobile phone is placed at the head of the bed, but according to Ms. Lin's recollection, she made a distress call in the living room, and the bedroom is not far from the living room, but the victim lost blood due to injuries and had to go to the living room to make a call, the reason is unknown, but the communication signal in the bedroom is good.

"You can add." Li Yi said.

Qin Gang unconsciously typed enter on the keyboard, "There is one thing I want to know. ”

Li Yi motioned to Qin Gang to stop tapping on the keyboard, "If you want to know something, see if I can answer it." ”

"The door of the rooftop has been replaced with an electronic door lock, and the IC card is used to open the door when entering, if the thief obtains the IC card through other means, the chance of picking it up does not exist, that is, you have to copy an IC card, is it so easy to copy?"

"The electronic door lock will also be equipped with a mechanical key to prevent the door lock battery from being unable to sense when the battery is short of power, so there are two possibilities, one is equipped with a mechanical key, and the other is to copy an IC card. The mechanical key is only available to the property management and the security guards who patrol the building, and they have no problem, so the only way is to copy the IC card. ”

Li Yi opened the search engine on his computer, entered the IC card, and clicked on one of the query results.

"If you look at this type, application scenarios like the East Lake rooftop, basically use this type because it's cheap. The memory chip in this card is divided into 16 sectors and 64 tracks, and each sector is fixed with 4 tracks, which can store 512K information. ”

When Li Yi said this, Qin Gang was already in awe.

"Each card has a fixed physical card number, the card number rules are defined by the manufacturer, some are 10 digits, some are 13 digits, different manufacturers will be different, but the manufacturer's basis is the type of card, different types and different lengths, which has an industry standard, just like the mobile phone 4G module we use, the world will adopt this standard."

"Does it have to be 10 bits or is the maximum length no more than 10 bits or 13 bits?"

"Yes, when each card leaves the factory, this physical card number will be written into the 0 track of the 0 sector, and it can only be written once, so the physical card number is unchanged. However, the card can be encrypted, the encryption algorithm is the standard defined by the manufacturer itself, and the key will be fixed by the card writer to write the third track of each sector. Under normal circumstances, as long as the user has no special requirements, the IC card and card reader given by the manufacturer will read the physical card number of 0 sectors and 0 tracks by default, and the physical card number standard is non-encrypted, so buy it back and just find someone to install it at the door, and the card will be issued directly to the user with the card bought by the manufacturer, saving time and trouble. I think that's the way East Lake operates, they are not a secret unit, and there will be no requirements for the security application level of IC cards, so you only need to have a computer and a card writer to easily copy N IC cards. ”

"I forgot to record a video for you, you can really start classes online, I, a complete layman, understand everything when I hear it, why don't you learn so many things in a day, and you really throw yourself into the ground." Qin Gang said.

Immediately, Qin Gang asked again, "In fact, copying the IC card is simpler than matching a mechanical key, you don't need to go out, you can place an order online, and as soon as the express arrives, you can complete it at home, which is too unsafe." ”

"Yes, but you have to have someone else provide you with the source card, or copy something."

Qin Gang nodded, "No matter how complicated and safe the measures are, as long as there is an internal collapse, they will be vulnerable." ”

Li Yi picked up the mobile phone on the table, "Teach you a simpler way to copy, you don't need to buy a card writer." ”

Qin Gang pricked up his ears.

"The prerequisite is that the mobile phone must have an NFC module, and this module can identify the IC card. Then go online to download a card writing APP application, search in the application market in the mobile phone, the search results should be full of screens, install one at will, most of them have card reading and writing functions, and the rest of the operation you know. ”

Qin Gang was taken aback, "This is too hip-hop, a mobile phone can copy the card, in the early years, there were shops on the street that specialized in helping people make IC cards, but now they must all go out of business." ”

"The advancement of electronic technology is advancing day by day, and in the early years, the streets were full of shops selling DVDs, can you still see it now? Keep pace with the times, and our industry is no exception. ”

Qin Gang nodded thoughtfully.

"What do you say Ms. Lin is trying to hide? Is it that important, ignoring her injuries to create time for the thief to escape, or whether she must deal with something before she can call with confidence. Qin Gang asked.

Li Yi has been thinking about this question all night and can't figure it out.

"Let's not be in a hurry to define it, at least there is no complete chain of evidence at present, it is not suitable to have any tendencies, let alone make any conclusions, which is contrary to our profession and profession."

"That'...... How did you start to break through. Qin Gang stood up and walked back and forth in the office, looking a little impatient.

"If the suspect has not been able to return to the case, and Ms. Lin has been keeping her mouth shut about the real process that happened on the night of the crime, this case will really hang here, Team Liu has made a not difficult definition of this case, I feel that he thinks that we can report the closure of the case in two or three days, and he is troubled."

Qin Gang kept walking around, shaking Li Yi a little dazzled. However, what Qin Gang said was reasonable, after all, in the entire case, only Ms. Lin was the victim at present, and there was no reason to interrogate her. ”

One of the key points in the case is the suspect, he appeared at the scene, and he was also the first person to experience the scene, the complete process that happened that night, there is no doubt that this person is the clearest, as long as he is brought to justice, all doubts can be easily solved.

But where is this guy? If the suspect is a wandering criminal, then he will not turn back, but wander around, during this period, if the thief does not commit another case again, it is difficult to trace and lock the trace, as time slowly goes by, perhaps, it will become a backlog again, and the wish of Team Liu is afraid that it will be disappointed.

"Let's go, go to the wholesale market, follow the vine and touch the melon, that's what we're doing, the sooner we can bring that guy to justice, the better."

"Are you sure we're starting the traditional route of sea fishing?" Qin Gang asked.

"The road is all out of the road, it's better than us scratching our ears and cheeks in the office and going on the road."

Li Yi jumped up from his chair.