Diary of a Criminal Investigator

"Hehe, you won’t guess how I killed her, will you?"

Dong Jun laughed a bit hysterically.

His eyes filled with hysteria after revenge.

However, Wang Zhaokai could only nod.

Even though a lot of evidence now points to Dong Jun as the killer of Qin Weiwei.

But how he committed the locked-room murder is still unclear to the Criminal Investigation Team.

"Actually, it’s quite simple to achieve this..."

It’s hard for people to keep a secret.

Especially someone like Dong Jun.

Having done something without anyone knowing, killed the person he longed to kill for years, yet in the end, having no one to tell, keeping it buried in his heart, this process is quite painful.

As the old saying goes, not returning home with wealth is like walking at night in a brocade robe.

If you do something, you must let others know.

Otherwise, what’s the difference from walking at night in a brocade robe?

This murder case, Dong Jun planned for a long, long time.

Since Qin Weiwei moved into this building three years ago, Dong Jun had been thinking about how to kill her.

The initial plan was simply to stab her to death directly, to avenge his son, and that would be it.

But later, he slowly started pondering how to kill her without exposing himself.

Poisoning?

Gas explosion?

Car accident?

Dong Jun thought of many methods.

In this process, Dong Jun also deliberately created opportunities to come into contact with Qin Weiwei.

At the beginning, Qin Weiwei was highly wary of Dong Jun, even though there was a significant age gap, as a single man, Qin Weiwei naturally protected herself instinctively.

"But I had no such thoughts, approaching her was only to study how to kill her better."

This deliberate approach by Dong Jun, without any intention of a romantic relationship, was seen by Qin Weiwei as neighborly goodwill.

"Moreover, I was the one who did her home’s renovation, so we slowly got familiar."

In Qin Weiwei’s eyes, Dong Jun was like an older brother who looked out for her.

Especially because Dong Jun worked in renovation, he was familiar with these things around the house.

So whenever anything like a faulty tap or a broken light happened at Qin Weiwei’s home, she could rely on Dong Jun to fix it.

Dong Jun himself was a warm-hearted person, getting along well with the neighbors upstairs and downstairs.

Qin Weiwei grew more at ease with him.

"Like this, more than a year passed, and I hadn’t found a particularly good method, one that would both kill her and allow me to escape legal punishment."

"Later, by chance, I found out she had a brain condition."

"Once, she fainted. At that time, I thought of killing her, but there were other neighbors present, so I couldn’t do it."

"I had no choice but to help the neighbors take her to the hospital."

"The doctor said her condition was quite serious, and she couldn’t have any intense emotional changes, or it might endanger her life."

"When I returned, I came up with a plan..."

The process of Dong Jun’s murder was more or less like Lu Chuan deduced.

Using his relationship with Qin Weiwei, Dong Jun often used her home WiFi.

And it was sharing this WiFi that inspired Dong Jun with a way to kill.

On the day of the incident, Dong Jun deliberately chose a pre-arranged time.

At that time, Qin Weiwei’s ex-boyfriend, Zheng Gaoxue, had visited her.

Dong Jun saw this as a once-in-a-lifetime opportunity.

The murder method he devised was flawless, making it appear that Qin Weiwei died naturally.

Moreover, should anything go wrong, the only person who had contact with Qin Weiwei that day was her ex-boyfriend, Zheng Gaoxue.

"She broke up with her ex-boyfriend over money, and it ended quite unpleasantly."

"So if you find that Qin Weiwei didn’t die naturally, you would naturally shift the suspicion to Zheng Gaoxue."

As for the murder method, Dong Jun knew that Qin Weiwei usually returned home late.

And she had a habit of taking a shower.

That afternoon, after Qin Weiwei left for work, Dong Jun tampered with her home’s electrical panel.

That little black box, they often used during renovations.

Some people liked to have light strips installed in their living rooms, and this little black box was a device to control the on-off flow of electricity to the light strips.

With it, the light strips would flicker on and off at times.

"With this thing installed, when Qin Weiwei came home, she would think there was an electrical issue, perhaps a poor connection, and she would definitely come to me."

Because she was familiar with Dong Jun and anything wrong with the home’s electrical or plumbing, she would ask Dong Jun to help.

Taking advantage of this opportunity, Dong Jun entered Qin Weiwei’s home and wrote those four words on her bathroom mirror.

"She owes me a life!"

"I must make her repay it!"

After writing those words with soapy water, Dong Jun knew that Qin Weiwei would surely go to shower.

This way, as soon as Qin Weiwei turned on the hot water, the words would slowly emerge from the steam in the bathroom.

"The apartment has poor soundproofing, I can hear the sound of water running when they shower."

"Then, when she was almost done showering, I used a phone connected to their WiFi to play a ghost movie."

"Along with the flickering household lights, damn it! Scared her to death!"

Sure enough, Dong Jun’s objective was achieved.

After taking a shower, Qin Weiwei, under this series of manipulations, suffered a recurrence of her brain condition, leading to a severe cerebral hemorrhage.

"So how did you get into her house?"

"I have a key to her house."

Dong Jun sneered, "I did her home’s renovation. I kept a key back then, I could enter her house at any time."

"But... what I don’t understand is, how did you know she was murdered?"

When being questioned by the police, Dong Jun was very calm because he thought he had done it flawlessly.

Writing with soapy water on the mirror would eventually evaporate over time, leaving nothing behind.

And Qin Weiwei’s cause of death was indeed a cerebral hemorrhage, and that’s what any investigation would conclude.

Then there’s the locked room.

When Dong Jun left, he locked the door from the outside, creating the illusion that Qin Weiwei was alone in the room.

No one knew he had been there that night.

So how did the police find out?

Wang Zhaokai picked up the autopsy report on the table.

"It’s simple, because you moved the body!"

Moved the body?

"How did you know I moved the body?"

"Impossible!"

Dong Jun couldn’t believe it, he had acted after Qin Weiwei died.

Moreover, he took measures to clean the body.

Couldn’t have been discovered.

"It’s impossible for you to find out! I cleaned all the traces, even dressed her in clothes... yes, I even wore gloves, and wiped the floor clean, no footprints could be left..."

This is the part that Dong Jun couldn’t understand.

He had clearly cleaned all traces thoroughly.

Why were the police so certain that Qin Weiwei was murdered?