"The deceased's house is also considered a related crime scene. Since we can't determine the cause of death, we must investigate everything related to the deceased. To avoid unnecessary trouble, we need to be well-prepared during the investigation to prevent leaving personal clues. If you touch a doorknob directly, your fingerprints will be left on it. How should we identify those fingerprints then?" Wang Shen had high expectations for his subordinates at work. While Wang Shen was a rather easygoing person in life, he was quite fastidious at work. He disliked people who hindered his work, and he would directly point out any mistakes his subordinates made.

Hearing Wang Shen's words, the young policeman silently lowered his head and said sorry. Wang Shen waved his hand and then gestured for everyone to put on gloves. After putting on the gloves, Wang Shen turned the doorknob, but the door did not open. Sure enough, the door remained locked. Wang Shen stood at the door for a while, then instructed the policeman beside him, "Go find a locksmith."

"Huh?" The police officer on the side was a little confused and hesitated for a moment. Then, the police officer standing to Wang Shen's left suddenly responded with "Okay" and disappeared into the stairwell.

Wang Shen frowned, his eyes slightly closed, seemingly deep in thought. Everyone in the police station knew it was best not to disturb him when he was deep in thought. At this time, he was usually absorbed in images of his crimes. And, moreover, he least wanted to be disturbed at this time. The remaining officer, seeing Wang Shen's expression, only dared to stand quietly to the side, awaiting his instructions.

The wait was a bit long this time; more than half an hour later, the young policeman who had just left finally arrived with a locksmith.

When Wang Shen saw the locksmith, he greeted him politely: "Thank you for your help."

The locksmith nodded, then placed his toolbox on the ground, took out some suitable tools from the bag, walked to the door, and prepared to unlock it.

"Wait a minute," Wang Shen interrupted the locksmith's unlocking work. The locksmith and the two policemen looked at Wang Shen with suspicion. "Sir, please check if the lock has been tampered with. Also, please put on some gloves."

The locksmith nodded to Wang Shen and took a pair of gloves from a nearby police officer. He put on the gloves, bent down slightly, and focused his eyes on the lock and keyhole while his hands worked on the lock cylinder. After a while, the locksmith straightened up and faced Wang Shen, saying, "From the outside, there are no signs of tampering with the lock cylinder. How about this, after I unlock it, I'll check the cylinder for any further signs of disturbance?"

Hearing the locksmith's words, Wang Shen silently nodded. With Wang Shen's approval, the locksmith began the unlocking process. Since confirming Han Lin's death, Wang Shen's mood had been heavy. There were two main reasons for this. First, the cause of Han Lin's death remained a mystery to Wang Shen. Even now, he couldn't fathom what could have caused Han Lin's demise. While it wasn't certain whether Han Lin had committed suicide by jumping, what if it was? Why would Han Lin have taken his own life? Second, Wang Shen felt a pang of self-reproach. He blamed himself for being too cruel, for insisting on uncovering the so-called mastermind. If Han Lin hadn't been taken to the police station immediately, perhaps this tragedy could have been avoided.

While Wang Shen was still lost in self-reproach, he heard a crisp click, and the lock was opened. The locksmith, twirling his tools, glanced at Wang Shen with a smug smile. Wang Shen nodded to the locksmith, signaling him to open the door. The locksmith, receiving Wang Shen's signal, turned back and gently pushed the door open a crack. But before the crack was wide enough, with a click, the door jammed again.

Wang Shen, standing behind the locksmith, hadn't yet figured out what was going on. His brows furrowed slightly, and he asked, "What's wrong?"

“There’s a chain inside this door, and it’s jammed by it. The lock cylinder hole is too small; even if we disassemble the entire lock cylinder, it will still take some time to open the chain.” The locksmith released the door handle, straightened up, and shook his head helplessly at Wang Shen.

After listening to the locksmith's words, Wang Shen nodded and replied, "There's not much I can do. Please remove the lock cylinder and open the door."

The locksmith nodded, squatted down, rummaged through his toolbox and found some new tools, then continued working on the lock cylinder.

Wang Shen watched the locksmith work for a while when his phone suddenly rang. "Hello, has it been confirmed? Okay, I'll be right there." The call was from Liang Zichen. Liang Zichen had already identified all the suspicious individuals by reviewing surveillance footage from the target time period.

"You two stay here. Once the door opens, protect the scene first, then notify me immediately," Wang Shen said to the two police officers behind him before leaving the stairwell.

After Wang Shen went downstairs, he asked the community security guard and soon found the community's surveillance room. Seeing Wang Shen enter the surveillance room, Liang Zichen immediately stood up from his seat, pointed to the paused image on the screen, and said, "Captain Wang, according to the clues provided by the building manager of the deceased's apartment building..." Liang Zichen glanced at the property management staff standing beside him as he spoke. "From the time Han Lin returned home yesterday until the incident, only ten non-residents entered and exited this apartment building. Of these ten, six were wearing delivery uniforms, so we can be fairly certain they were delivery drivers. As for the other four, according to the property manager, they all went to a resident's home on the third floor for dinner. I just had the property manager call that resident to confirm the identities of these four people; they are all that resident's colleagues." Liang Zichen recounted the identities of all the suspicious individuals he had discovered. After finishing, Liang Zichen looked at Wang Shen, whose brow was slightly furrowed.

"In that case, it seems that no suspicious persons have entered or left the deceased's apartment building." Wang Shen said, while clenching his fist and gently tapping his chin.

"By the way, notify the bureau to contact the food delivery company and see if we can get the delivery addresses of those six deliverymen last night to see if the deceased ordered any food." After Wang Shen finished speaking, Liang Zichen nodded.

"Thank you so much. We'll need your cooperation in the future, so please provide as much assistance as possible." Only then did Wang Shen notice the property manager standing to the side. The worry on Wang Shen's face eased, and he smiled and shook hands with the property manager.

"That's for sure," the property manager replied politely.

After exchanging a few pleasantries with the property manager, Wang Shen took Liang Zichen back to Han Lin's house.