Liu Na handed Jiang Zhengkai the items. “Inspector Jiang, here is a report of the noise a.n.a.lysis of the room on the night Hui died. Xue Na just delivered it on request of Commissioner Yao.”

“Really? The central bureau was quite fast this time.” Jiang Zhengkai pointed at Liu Na's computer, “We'll use your computer! Play it for me.” Liu Na took the disc back from Jiang Zhengkai and inserted it in her computer. Meanwhile, Jiang Zhengkai turned his focus to the report.

“Si la…… ah oh……. ha eh……” A series of weird sounds came out from Liu Na's computer. “Inspector Jiang, these were the original sounds from that night.”

“That's right!” Jiang Zhengkai squeezed the report in his hands. “Play the sounds with the digital alteration.”

“Hui, give me back my life! Hui, give me back my life!” A woman's low voice spread through the office and caused gooseb.u.mps to rise on all those who heard it.

“Sister…… Sister Xiu……” Jiao heard the voice and stared at Liu Na's computer, terrified. Jiang Zhengkai turned his focus to Jiao and simultaneously placed his arm around her shoulders. “Ziyuan, calm down! Calm down! Who is it? Xiu?”

Jiao's body trembled slightly as she nodded affirmatively. “Yes! It's her. That's definitely her! This is definitely her voice.” Just by her reaction, Jiang Zhengkai could tell Jiao was very disturbed by the tape. “Ok! It's enough. Stop playing it. Turn it off.”

Liu Na closed the computer's media player. “Inspector Jiang! The voice kept repeating the same line after.” “Ok, I got it,” Jiang Zhengkai replied half-heartedly and looked at Jiao again. “Are you okay? Do you feel any better?”

“Yes,” Jiao nodded. Then she raised her head and looked at Jiang Zhengkai, shocked. “Honey, could…… could it be that she…… she is still alive? But…… but her voice is too terrifying.”

“Are you sure that you heard correctly?” Jiang Zhengkai asked, somewhat doubtful. Could the voice really be Xiu's? Xiu is actually still alive? If Xiu is really still alive then Lian must have gone crazy that night precisely because she actually saw Xiu?

“I'm positive that it's Xiu's voice.” Jiao affirmed as she calmed down. Jiang Zhengkai had previously reminded her to not call Xiu “Sister Xiu” in public.

“So it looks like she may still be alive then?” Jiang Zhengkai rubbed his nose with the same hand holding onto the report. “But this voice is really strange! It's not on the same frequency as a normal voice. The pitch had to be digitally raised by the technical staff from the central bureau before it became audible. In other words, it's an infrasonic wave and can't be heard normally. But what's even more strange is that it was recorded and then even heard by us.”

Jiao ruthlessly reprimanded, “What we heard were those 'si si la la' sounds right? Unless you straight up heard the voice?”

“Haha! Looks like you're back to normal now you silly girl.” Jiang Zhengkai patted Jiao's head and then put the report on Liu Na's desk. “Ok! Liu Na put the report away! I'll take another look again tomorrow morning. Let's follow the original plan and head to the alley.” Then Jiang Zhengkai pushed Jiao out and they left the office together.

When both of them entered the car, Jiang Zhengkai said as he turned on the ignition, “Honey, what you said seems to make a lot of sense. We couldn't hear the voice, but how could Hui and the others hear it?”

Jiao shook her head as she replied, “I don't know. Honey, if Sister Xiu is still alive, then why would that sound clip from the room be an infrasonic wave?”

Jiang Zhengkai shrugged. “Like you, I don't know either. Perhaps it's because infrasonic waves can be transmitted a long distance? Or maybe it's so that the killer can hide themselves?” Then he added, “I'll ask Mu Mingyuan tomorrow. I'll see if a guy from Material Evidence can help us come up with an explanation.”

Inside the alley, Lu Xiaoqiang and Zhang Nan had already chosen a place. It was a two bedroom apartment that was relatively isolated from the rest of the buildings. Of the two rooms in this place, one was located on the south side, while the other was on the north. A corridor in the middle linked the bedrooms, kitchen and bathroom together. Lu Xiaoqiang and Zhang Nan had been waiting to accompany Jiang Zhengkai to inspect the rooms' every nook and cranny.

“Good! This place isn't bad at all.” Jiang Zhengkai said after he finished inspecting the place, satisfied. “Very suitable to monitor and easy to deploy surveillance in.” He looked towards Zhang Nan and asked, “Zhang, have you already set up the surveillance equipment?”

“We're nearly finished,” Zhang Nan replied. “The installation inside the rooms is complete. The installations outside will be done tonight.”

“Zhang…… Zhang, when the time comes, which room will we be using?” Jiao always slightly uncomfortable in front of Zhang Nan since he had seen her before. Although Mu Mingyuan had helped her with new makeup and Zhang Nan hadn't been able to recognise her in previous instances, Jiao was still worried that there would come a day where Zhang Nan would recognise her.

Zhang Nan pointed at the room on the south side and replied, “Oh, you will be using the south room. The conditions there are a bit better. More importantly, it is easier to install surveillance on all sides of that room. The other room will be used as the surveillance room, and there will be two or three officers on guard.”

“I was wondering, could we modify the floor and walls of the bedroom?” Jiao glanced at Zhang Nan and then looked towards Jiang Zhengkai again. “Do you think that the killer can escape from the room from another direction?”

Jiang Zhengkai, Zhang Nan and Lu Xiaoqiang all heard Jiao's question and the three of them looked at each other but none of them were in a hurry to express their opinion. Going by the scene of the first case, it was very likely that the killer hadn't escaped through the doors or windows. Unless they were actually the Daoist Priest from Laoshan Mountain1 and could directly walk through walls? Now it seemed like Jiao's suggestion to modify the floor and walls actually had some logic behind it; perhaps this would be what prevented the killer from escaping?

Finally, Zhang Nan spoke up. “I think that Miss Ren's idea is pretty good! How about this, for the next two days we will continue preparing; we will inspect the floor and walls again. Then…… then we will install a metal protective net inside the wall. This way, we will have the whole room under surveillance.”

Jiang Zhengkai smiled humorously. “Ha! This method is pretty good. When the time comes, I will be in a metal cage. Don't forget to modify the windows and doors for me as well! When the time comes, we can even let lions and tigers in without fear that they'll be able to get out!” When he finished saying this, Jiang Zhengkai smiled bitterly to himself. What exactly were they doing? Why did it feel like they weren't trying to catch a killer, but rather a ghost?

Jiao nodded her head, satisfied. “Thanks, Zhang.” She didn't care what Jiang Zhengkai thought in regards to her suggestion. She wanted the scene to be 100% safe. She couldn't let Jiang Zhengkai die.

“Ok! If there's nothing else, then should we all go out and get some food?” Zhang Nan looked at the other three in the room. “We've all been working together for half a year and we haven't ever gone out together. By chance, Miss Ren is also here. Jiang, you don't have any more excuses right?”

“That won't do, I haven't been given the go ahead!” Jiang Zhengkai looked at Jiao with a smile plastered all over his face. Jiao noticed that Jiang Zhengkai was looking at her and glared at him fiercely and said with disdain, “I can't be bothered to care about you! I don't know who you're trying to get a go ahead from.”

“Haha! Look how considerate and understanding Sister-in-law is.” Zhang Nan knew from Jiao's expression that she wasn't opposed to his suggestion. “Let's go then! Park the car at the station and we'll take a taxi! Tonight we are going to drink! No one is allowed to back out.”