Diary of a Criminal Investigator

"It’s not hard to understand. The same carp costs ten yuan at a street-side eatery, but how much do you think it would cost if you put it in a five-star hotel?"

"What’s important is not the fish, but where the fish is."

"Su Xiaogang is packaging ’respectable family’ at the fitness club. Even though some of them look average, the price remains high."

"Haven’t you heard the saying that men love to do two things the most?"

"First, persuade women of the night to lead a decent life."

Zhang Hui, hearing this... shit, that makes sense: "What’s the second thing?"

"Hehe, drag respectable women into the fold."

"Shit... that’s really true!"

Zhang Hui looked at Ren Qiang with admiration in his eyes.

Having been by Ren Qiang’s side for years, Zhang Hui thought he had learned most of Ren Qiang’s skills, but now he realized there was still a long way to go.

Cracking a case isn’t just a matter of technique. In fact, solving a case is all about understanding the human psyche.

If the investigators can figure out the killer’s train of thought, then their capture is not far off.

At the end of the day, isn’t the killer just playing a game of hide and seek with the police?

Concealing the motive for murder, hiding the body, hiding the weapon, etc. The killer’s true purpose is singular: to hide themselves.

If the thoughts and ideas of a killer can be deduced by the investigating officers, then unraveling the mystery and capturing them is surely not far off.

In the Crime Scene Investigation office, Liu Guodong and Lu Chuan hadn’t left. After Lu Chuan finished comparing Su Xiaogang’s footprints with those at the crime scene, it was already very late.

In fact, when Ren Qiang and Zhang Hui brought Su Xiaogang back, Lu Chuan only needed a glance to know this person wasn’t the killer.

His height was off.

Although Wu Xiaogang was strong and 1.81 meters tall, and the killer modeled by Lu Chuan was estimated to be between 1.82 and 1.84 meters tall, the difference was minimal but significant.

In Footprint Identification and Analysis, the science of using footprint lengths and other data to calculate the height of their owner is very precise.

Lu Chuan’s calculation was actually 1.83 meters.

Giving a range considered margin for error.

The height falls within this range, it wouldn’t be less than 1.82 or more than 1.84, not even by a centimeter.

Sure enough, when the final comparison was made, Su Xiaogang’s footprints were completely different from those found at the scene.

Even if two people have the same foot size, their footprints will be different.

After all, many people wear the same size shoe.

People between 1.70 and 1.75 meters tall can likely wear size 42 shoes, but because of differences in weight and walking posture, each person’s pressure point on their foot is different.

For instance, some people put more pressure on the outer foot, some on the inner foot.

Some people walk heel-first, others shuffle.

Su Xiaogang’s step had more pressure on the outer foot, but the killer’s footprint had more pressure on the inner foot.

Early the next morning.

Zhang Hui headed to Haizhou Science and Technology University.

In the lab, Zhang Hui met Wang Qianqian.

"You are..."

"Hello, Classmate Wang. I’m Zhang Hui from Haizhou City’s Criminal Investigation Team. There’s some information I need to verify with you."

Criminal Investigation Team?

Wang Qianqian was slightly taken aback; she didn’t expect a police officer to come looking for her.

Other classmates of Wang Qianqian also looked at her curiously.

"I... I don’t think I’ve committed a crime?"

"It’s about something else, can we talk?"

Zhang Hui didn’t go into details. He’s a detective, not a community officer, and Wang Qianqian’s part-time work wasn’t his concern.

"Go on, the sooner the better."’

Her mentor nodded, and she left the computer, standing up: "Come with me, there’s an empty classroom next door, let’s talk there."

In the classroom, Zhang Hui didn’t mince words and took out a photo of Zhang Xiaofeng.

"Wang Qianqian, do you know this person?"

Taking the photo, Wang Qianqian turned pale.

After all, the two of them had a close encounter at the Nebula Hotel just the day before yesterday; how could she forget so soon?

"I... you guys..."

Wang Qianqian never imagined that after just a few times, the police would come.

"Wang Qianqian, don’t be nervous. I’m a detective. Your matters with Zhang Xiaofeng are outside my jurisdiction. I want to ask, the day before yesterday at noon, after you and he... do you know where he went afterward?"

Hearing that Zhang Hui wasn’t there to arrest her, Wang Qianqian breathed a sigh of relief.

This was a school, after all. If the police took her away for that sort of thing, she probably wouldn’t be able to continue as a graduate student.

"I... I really had no other choice. My boyfriend graduated and didn’t have a job, I..."

Wang Qianqian began confessing everything from why she went down this road.

She had indeed met Su Xiaogang at the Platinum Fitness Clubhouse, but unlike others, Wang Qianqian went there just to work out.

It was only later, to buy her boyfriend an Apple phone, that she had her first time.

That time, she earned ten thousand yuan.

Subsequently, whenever her boyfriend wasn’t around and she had time, she would take on clients.

She earned at least five thousand each time, up to eight thousand to ten thousand.

"That man... was introduced to me by Su Xiaogang. It was my first time meeting him."

"At noon that day, there was a moment in between when someone called him on WeChat, seemed like something important, but I didn’t hear what was said."

"How did you know it was important?"

"Um... because he was in the middle of... but when he saw the call on WeChat, he stopped, took the call, and then returned..."

Zhang Hui nodded.

Wang Qianqian is very pretty and was only doing this part-time, and for him to stop at such a critical moment meant it was definitely something important.

"Did you notice anything else unusual?"

"Um... the person on the other end seemed to be a woman."

"Why? Didn’t you say you didn’t hear what they were saying?"

"I guessed because when he returned, he was even more... excited. Very soon... he..."

"Moreover, he mentioned Xiaohui."

Xiaohui?

"Is it a name?"

"Probably. That’s what he called out in the end."

"When did he leave?"

The Nebula Hotel’s surveillance cameras were practically useless. Maybe to avoid leaving evidence, they’d been broken for over a month and hadn’t been fixed.

The colleagues who went to investigate didn’t find the last footage of Zhang Xiaofeng’s disappearance.

"Around one-thirty in the afternoon, I’d say. I was worried about being seen, so I had him leave first. I followed behind and saw him heading into Culture Lane before I caught a ride back to school from the square."

Culture Lane?

What did Zhang Xiaofeng do in Culture Lane?