The third missing person was also a sex worker named Little Qin. The time she went missing was in the evening of August 3rd. Before going missing, she sent three voice messages to her friend. The first said she was about to arrive at the restaurant she was meeting at. The second message said that there seemed to be a suspicious person following her. The third was only a short scream. There had been no contact since.

Her friend didn’t call the police, but went to find the gang behind her. The first thought of the brainless triad members was that the competitors had done it, so they went to their door to look for her. There was almost a knife fight between the two sides. If the police hadn’t been investigating this case over the past two days, this case wouldn’t be exposed.

After listening to Lin Qiupu's words, Chen Shi said, "The sex workers in the clubs of the city are basically all backed by triads. They won’t report to the police if the girls disappear. The murderer is using this mentality to select them as targets."

Lin Dongxue lamented, "Women are always unlucky."

Lin Qiupu played the audio left by the missing person. Everyone listened together. The first voice message seemed to be her walking on the road and her voice was breathless. The missing person said, "Amy, I’ll be here soon. You should order first! I met a nosy customer when I was about to leave work. I’ll tell you about it when I arrive."

Chen Shi asked, "Who’s this customer?"

Lin Qiupu responded, "We’ve asked, but Little Qin's workplace repeatedly emphasized that they are a serious foot massage shop and wouldn’t allow us to investigate. The surveillance monitor, swipe records, and appointments were all kept from us."

"Just close down their shop."

"Yesterday, they closed the store by themselves. The manager disappeared cleanly and couldn’t be checked at all. Isn’t that annoying?"

Chen Shi secretly suspected that the suspect may have had a "business" contact with these women, but their workplaces only thought about self-preservation when things happened, so they weren’t able to investigate at all.

They continued to listen to the messages. In the second audio message, the missing person seemed to be walking very quickly and the voice trembled slightly. "Amy, it seemed like someone was following me, but I think I lost them. It scared me to death.”

Chen Shi said, "Replay it again!"

After hearing it three more times, he said, "There’s a train in the background."

"It may also be the subway." Xu Xiaodong said.

Then, there was the third piece of audio. There was only a short "ah" in the audio, followed by a violent crashing noise. It may have been that the phone fell to the ground, or the owner was attacked.

After listening, everyone was silent and dazed for a while. Lin Qiupu said, "Little Qin's money in her bank card was transferred away in the early hours of August 4th, and the card that received the money was the suspect Zhang Xiao. So, we have full reason to believe that Little Qin has already been killed. How can we find her? The current clues on hand are only these three audio clips."

"Did her friend say where they were meeting to eat?" Chen Shi asked.

Lin Qiupu found a detailed map of the city and marked the restaurant they arranged to meet at with a pushpin. Chen Shi asked, "What about her workplace?"

"Here!" Lin Qiupu marked that as well.

Everyone leaned forward to study it. Chen Shi was a driver and knew the roads better than anyone else. "There’s no railroads between these two points. The nearest one is half a kilometer away. Little Qin didn’t need to go around this road!"

Lin Qiupu took out a few photos that were downloaded from the Internet. "According to her friend’s recollection, when Little Qin disappeared, she wore these clothes."

The outfit included high heels, a tight dress, and a small shoulder bag. It wouldn’t have been easy to move in them. Chen Shi suddenly said, "Why did we think about the problem so rigidly? Hearing the sound doesn’t mean that it’s nearby. Some places are far away, but the noise can be clearly heard... Dongxue, Xiaodong, and I will check it out and tell you the results tomorrow."

"Okay!"

The three drove to the place near Little Qin's workplace and took her photo to inquire around the area. An uncle who sold boiled corn and roasted red taro downstairs knew what the girl with thick makeup that came down from this building every day did as a job. He had seen this girl, but couldn’t remember the time.

Chen Shi said to Lin Dongxue, "We should buy you the same clothes and simulate it."

"Huh? Why are you always torturing me?"

"Only you can wear these kinds of clothes."

"Stereotypical thinking. Can't you wear it? Can't Xiaodong wear it?"

Xu Xiaodong was afraid that the two really would discuss it and ask him to wear women's clothing, so he said, "I don't think it's necessary to simulate it. Listen to the audio carefully to see what we’re missing. We can look for it at the scene."

Right now, they didn’t have a lead. The three had to find a secluded place to listen to the audio messages again.

After listening to it countless times, Chen Shi asked, "Have you noticed that there’s no high heel noises in the first audio message? However, it’s very clear in the second audio."

Xu Xiaodong suggested, "Maybe it’s because she was running in the second message?"

Chen Shi was also unsure and asked Lin Dongxue, "Can you hear the sound when walking in high heels?"

"Uh…"

In the spirit of seeking the truth, the three of them experimented with it and bought a pair of high-heeled sandals around the area. Lin Dongxue, who rarely wore high heels, was quite unaccustomed to them. She walked and recorded a similar message for Chen Shi.

Chen Shi opened it and listened. In the voice message sent by Lin Dongxue, he could very clearly hear the sound of the “dook dook dook” noise the high heels made.

Xu Xiaodong said, "That’s strange. Did she take off her shoes?"

Lin Dongxue suddenly realized and smiled. "I understand now. A girl's common problem. They’ll say they’re almost there even when they haven’t left at all. She hadn’t put on high heels at that time!”

"But she's panting. Perhaps..." Xu Xiaodong was a little embarrassed to finish his sentence.

"She shouldn't be ‘working’." Chen Shi said, "Listen carefully. You can hear the sound of vehicles on the road, and the panting is at a set rhythm... Exercise. She was exercising. Maybe in a gym or something!"

Chen Shi opened the map on his phone to check. There was a fitness club nearby. They went and asked the staff there, who said that Little Qin did come to go to the gym every afternoon. She rented a locker there and would change every time she came and put on fitness clothes and shoes.

Chen Shi asked the staff to open the locker and looked at it. Sure enough, there were sneakers, sportswear, towels, and other insignificant personal items. Among them was a box of matches with the contact details of a winery on it.

Chen Shi took pictures of the contact information on the matchbox and asked the staff, "Where does Little Qin generally exercise?"

The staff pointed to a row of treadmills by the window. "She comes here every afternoon to do cardio exercises. It’s generally not for too long. About 20 minutes to half an hour."

The three went to the area the staff pointed at. Lin Dongxue turned on the treadmill to test it and recorded a voice message very similar to Little Qin’s. Chen Shi said, "Your panting sound is still a little faint, indicating that Little Qin had been running for over ten minutes."

"No matter what, we’ve found the first point." Lin Dongxue smiled.