Guan Feng said, "Henry explained that the finance office has a security door with two sets of locks, one for him and one for Xu Qingxiu. Xu Qingxiu is our Chinese finance manager, and to open the door, you have to insert both keys at the same time and turn them."

Li Xiangdong asked, "So that means both of them have to be present at the same time?"

Guan Feng nodded and said, "It cannot be ruled out that someone has copied the key. I have already told Henry to hand the key over to the technical department for testing to see if it has been copied."

Li Xiangdong said, "The team leader is very thoughtful."

As they were talking.

Wang Xun walked in: "Team leader! The technical department's results are in."

Guan Feng took it, glanced at it, and frowned, saying, "There are no signs of damage to the lock cylinder?"

Wang Xun said, "That's right! Captain Chen said that the other party either entered through the window or opened the door with a key, and it was impossible for them to have broken into the door by force."

Guan Feng nodded.

He looked at Li Xiangdong and Huang Lili and instructed them, "You two take statements from Xu Qingxiu and the other person first. I'll go check on the technical department."

Follow Wang Xun out of the interrogation room.

Chen Xuewen was carefully examining the marks in front of the door.

Guan Feng asked, "Captain Chen, how is it?"

Chen Xuewen said, "There are no signs of damage to the lock cylinder, and the room is currently being inspected."

Guan Feng said, "Then let's take a look together."

He put on shoe covers and went inside.

Squeak!

The thick steel door opened.

The first thing you see is the typical layout of a finance office: two brown cabinets against the wall, with various financial documents on them.

On either side, two large safes stood on the ground, their doors open, revealing that they were empty.

Guan Feng asked, "What can you tell from the safe?"

Chen Xuewen said, "This is the simplest safe, with only a single combination lock. It's probably because the door is already very secure, so no additional security measures were set up. There are no signs of damage to the gears, so the other party unlocked it directly with the combination."

Guan Feng frowned again.

Password unlock?

This means that the possibility of insider involvement has increased further.

If the other party does not enter through the door...

Guan Feng scanned his surroundings.

A moment later.

My gaze was fixed on the two standing bookshelves on the wall.

If, apart from the main gate, there is anywhere else that people can enter...

That leaves only this place!

With the window open at the back, it's entirely possible to climb in from the top of the cabinet.

Guan Feng approached and carefully examined the marks on the bottom of the cabinet. He actually managed to figure something out.

"This cabinet... seems to have been moved!"

Guan Feng squatted on the ground, scanning the corners of the standing bookcase.

There!

The varying shades of dust create a striking contrast.

Guan Feng called Chen Xuewen over.

Chen Xuewen squatted down to take a look and exclaimed in surprise, "It really is! The dust here is light, clearly a trace left after the move. It's less than a centimeter off. Team Leader Guan, your eyesight is truly amazing!"

Guan Feng asked, "Can we determine the time of the movement by comparing the traces?"

Chen Xuewen glanced at it and nodded, saying, "No problem!"

A moment later.

Through trace evidence examination.

Chen Xuewen confirmed, "The time should be within the next one or two days."

Guan Feng immediately said, "This timing coincides perfectly with the timing of the cash theft case."

He glanced at the bookshelf.

He immediately rushed to the patrolman and said, "Bring me a chair in."

Wang Xun ran out.

They brought in a chair.

Guan Feng stood on the chair and peered at the top of the cabinet.

A cabinet that is about two meters tall.

Several footprints at the top are very conspicuous.

"These might be the footprints of the suspect who entered and exited! If the suspect climbed in through the window, because the cabinet was so close to the wall, there wasn't enough space, so they had to move the cabinet door, creating these marks!"

Others also gathered around to look at the footprints.

"It really is true!"

"Team Leader Guan, your eyesight is absolutely amazing!"

Guan Feng waved his hand and said, "It's too early to draw conclusions now. Captain Chen, I'll have to trouble you to determine the date of these footprints first. Also, Wang Xun, go and ask why the finance office is located here. Generally speaking, finance offices of this level are located in a separate room with a heavy security door and no windows. Has it been changed recently?"

Wang Xun nodded and ran off to inquire.

Chen Xuewen then stepped forward to examine the evidence with a trace inspection lamp.

After a moment, he confirmed, "Judging from the dust marks, it coincides with the time the cabinet was moved, which was within the last two days."

Guan Feng immediately said, "Then extract these footprints; I need to have them analyzed."

Chen Xuewen pushed up his glasses, frowned, and asked, "Team Leader Guan, these footprints on such a hard cabinet top can't be used as evidence to identify a suspect, can they?"

Guan Feng laughed and said, "That's right! The top of the iron cabinet is very hard and it's difficult to leave marks, like the tiles in Huang Youwen's house last time, but this time it's different."

He wiped the top of the cabinet with his hand, showing the thick layer of dust to the others.

"No one goes into the finance office for years, especially the top of the cabinet, which has been uncleaned for many years, resulting in a thick layer of dust on top, which provides a platform for footprints to bear weight."

"The suspect thought he was being meticulous, but he overlooked this detail, leaving us with an important clue!"

"Captain Chen, we'll need your help with the evidence gathering!"

Chen Xuewen exclaimed in surprise, "I never imagined that dust could be used as a material sample for footprint identification. This has broadened my horizons today."

Guan Feng said, "Captain Chen, don't be so polite. Once you've identified the suspect's characteristics, you can start bragging."

Chen Xuewen pushed up his glasses and smiled, "Okay! I'll extract it first! Let's try to get the results as soon as possible."

Guan Feng nodded and got down from the chair.

Wang Xun then said from the side, "Team leader, I just asked the finance manager, and he said it's a legacy issue. This was originally the office for the second phase of the project, but the finance department moved here after the project went into operation."

Guan Feng asked, "Wasn't that a coincidence?"

Wang Xun said, "It has been around for several years."

Guan Feng nodded, thus ruling out this possibility.

Wang Xun then asked in confusion, "If the other party entered and exited through the window, how did they manage to move the cabinet back to its original position?"

After all, there's no leverage point at the window; you can only push outwards, not pull inwards.

Guan Feng glanced at the door and said, "Perhaps they're leaving through the main entrance; there shouldn't be two locks inside, or perhaps..."

He considered one possibility.

If the other party can enter this house today, they can move the cabinet door back to its original position, or use some special tools to achieve the same effect.

He looked at Wang Xun and instructed, "I see a security camera with its light on at the entrance of the finance office. It should be running. Have someone retrieve the footage and check who entered and exited the finance office between 6 PM last night and when the missing accountant was discovered. Let's rule out other possibilities first!"

"yes!"

Wang Xun nodded immediately.

Guan Feng continued to examine the footprints for identification.

Five minutes later.

A police officer ran upstairs, panting and excited, and said, "Team leader! The surveillance cameras... the surveillance cameras are broken!"