Four cars—Rebecca's black SUV, and three police cars are parked outside the gate of Sergeant Rebecca Armstrong's private residence. All of her investigative team came in civilian clothes to her house to investigate—also following Lieutenant Chankimha's advice not to let Rebecca come alone to her house and starting the investigation by asking people in Rebecca's neighborhood.

All the photos left by the monster showing various different angles so that it can be concluded that she had stopped around several times, became one of the residents, or even infiltrated one of the houses just to monitor Rebecca's daily life.

Rebecca's home environment is a relatively quiet. Most of the residents are office workers who go out in the early hours of the morning, come home when the sun starts to set, and turning off their lights at night. There are even several housing units that are vacant because the owner is simply using the house as a property which will be resold in a few years after the price has doubled.

The arrival of the police officers did attract the attention of several people, but because they all came with tense faces like they were in debt, no one dared to approach because they were reluctant and chose to watch from a distance. They had all gotten directions from Rebecca when they were at the office—the young sergeant came wearing two salonpas plasters on the nape after coming home from the hospital in the afternoon to stay at Nam's apartment so she could go to work the next morning—so as soon as she got out of the car, her team immediately moving to spread according to their respective duties.

Some of the things that must be done after getting the warrant are visiting the houses around Rebecca's residence one by one to ask for permission to search, asking local people about the possibility of unknown people hanging around, as well as checking the CCTV cameras that are around there. Rebecca was still by the side of her car, staring at her own house like she was staring at something foreign and so far away.

Just imagining what might be there when she wasn't home sent chills down her spine.

In one of the police cars, Noey, who was originally standing in the yard with Heng and Freen, was seen running back to open the trunk of the car to get a small electronic device and returned to the yard to give it to Freen. To be honest, Rebecca still didn't have enough courage to go inside her house. But since it's her job to find clues that will lead her to the killer, she needs to fight that fear.

Using the remote to lock her car door until a loud beep sounded, Rebecca walked quickly over the small rocks stuck to the soles of her shoes to join her other teammates in starting a search of her own house. Casting a brief glance at Freen, Rebecca felt that she did not recognize the young lieutenant even though the two of them had spoken for several hours two days ago.

The woman's face looked unfriendly again, indicating that she was not interested in talking about anything other than work related. The cold eyes of the two light brown irises seemed to stab everyone's heart and made anyone who looked directly at them. If she wanted to, maybe Freen could kill people with just one look at that terrifying eye.

Even when Rebecca walked up to her, this Chankimha didn't bother to look at her or greet her but immediately asked her to go ahead and open the door of her house with the key that Rebecca had brought. Breathing heavily because she didn't want to make the tense atmosphere even worse, Rebecca carried out Freen's request without saying anything. Rebecca, as the owner of the house, stood at the door with the key in hand.

Noey, Heng, Seng, Irin, and Freen were behind her—all of them on alert and slowly removing their pistols from the holsters slung on their belts. As soon as the door was opened and a dark view of the house appeared in front of her eyes, Rebecca immediately grabbed her gun and flashlight from her belt, and slid inside with a wary gaze to the right and left.

"Seng, Irin, Noey. Upstairs." Rebecca whispered, stopping right by the stairs and using her left index finger to point at the steps leading to the second floor.

The three personnel whose names were mentioned immediately ran quickly up the dozens of stairs without producing a sound of tapping from their shoes which continued to collide with the marble floor. Leaving the three members to finish their business to search anything suspicious on the upper floors of her house, Rebecca led Heng and Freen to search all the places on the first floor.

The living room contains several sofas, an 80-inch television on the tv table with a home theater set on the right and left, several shelves full of books and a table containing several table decorations.

As Heng walked alone with gun in hand to head down the corridor to check the door to the closed front garage, Freen darted quickly beside Rebecca. A device resembling a remote control with a small black antenna sticking out at the top was gripped tightly in her hand. There is a bright yellow light that turns on and off at a medium tempo. The light's tempo was getting faster and faster when Freen approached one of the bookshelves containing various reference books related to medical psychology, and the latest laws in Thailand.

Until at one point, right on one of the books that Freen approached, it made the tool in her hand go crazy. The yellow light continued to flash and let out a loud hum that even Heng and Rebecca scurried towards it. Without waiting to be asked, Freen put the tool on the table and immediately pulled out some of the books. On one of the sidelines of the book, tucked into a small camera that is still active. The camera fell to the floor, right beside Freen's feet—she almost stepped on it if only Rebecca didn't hold her feet in place.

The young sergeant crouching down for the camera, holding the little thing up to her eyes to get a better view of the thing that had been spying on her life all along. The camera is very small. Smaller than her thumb, and maybe the size of a watch battery. Rebecca looked up, slightly surprised to realize that Freen was also looking at her with a deep frown. And just then, confirming that they were thinking the same thing, Freen immediately turned around to grab her device and moved to another room, leaving Rebecca still dazed with a small camera in her hand.

How did that monster come in and put something like this in her house without her knowing? Even though she always locked the front door and the balcony on the second floor when she left the house. She was also very sure that she never forgot to lock the gate and trunk. So... why did the killer get in without breaking the lock?

Talking to those closest to her, if I recall, Rebecca never gave a copy of her house keys to anyone other than her own closest family members. Even Nam who is almost like her own sister though. So... how come?

She felt her hands begin to lose the strength to hold. The muscles in her hands seemed to weaken so that her hands could only fall limply at her sides while Rebecca stood alone with thousands of questions that might never be answered. That strange feeling came back to attack her, making her whole body tremble.

The thousands of pairs of eyes returned. Gathered in her dark house, hiding among the black corners where the light doesn't touch. Everyone stared intently at her, like wild animals in the wilderness stalking their prey. Her heart was racing, making her very uncomfortable and nervous at the same time.

CRACK

Upset and overly frustrated she spilled just like that in one swing of the hand. The small camera was slammed on the floor with a bang by her, then because of the anger that blinded her reddened eyes, Rebecca stamped her right foot as hard as possible to shatter the electronic device until its shape resembled small white glass shards that contrasted with the floor of her house.

Who the fuck are you? What have I done to you to make you stalk me like this? Her emotions were completely messed up. With just a glance, one might catch red wheels appearing on her ears and face due to the hot blood pumping up her head. I swear, if you do the same with my family, I will make sure the law of the jungle will apply to you.

Rebecca walked into her work room, kicking the heavy teak door against the wall behind her. The rather large room was indeed dark, and Rebecca immediately turned on the light. Work desks, computers, printers, bookshelves, filing cabinets, cupboards filled with old rifles immediately appeared in her eyes. Without waiting any longer, she immediately unloaded all the contents of the desk drawers and dropped all the items in her filing cabinet and bookshelves onto the floor.

The young Armstrong reached into her trouser pocket for a pair of rubber gloves still wrapped in plastic. Hastily, she used it on both hands to avoid contaminating any other possible fingerprints on the books with her own.

When all of her books and folders were scattered on the floor, Rebecca put her gun and flashlight down on the table before crouching down to rummage through everything under her feet for any surveillance cameras or bugs that might be hidden there. One book flipped through the pages quickly, and when there wasn't anything she was looking for, Rebecca would toss it around the corner and then grab another book to do the same.

Unexpectedly, Rebecca found 4 small cameras and 2 bugs. She laid them all out on the table and pushed all her books away from her feet with a brute—she kicked them aside. She didn't care about the banging and crunching sound that was produced when the book hit the wall and the wooden shelf.

From outside the room, came the sound of hurried footsteps. It was clear whoever the footsteps belonged to was running in a hurry to her room now. "Nong! What happened?" a tall man—his head barely reaching the top of the door—bursted in a sudden. Rebecca could hear him cursing under his breath, perhaps surprised by the chaos in her work room. "Are you okay? What are you doing?"

"How—" Rebecca put her hands on the table, helping her to raise her body because her knees were no longer able to support her body weight. Not after she found horrible things in her study. "How do I live in this place without knowing that there's a crazy psychopath out there watching my every fucking move, Heng?"

"Again? Oh my God," Heng opened the door wider, taking a small glance at Freen who was running from the kitchen area to the living room and bending down to put something on the table, the man walked forward taking care not to step on anything. Close enough, he could hear Rebecca's breaths getting louder.

Heng opened the plastic seal for the evidence he was carrying. Carefully, he put all the objects Rebecca found into the plastic and closed it again. The room was a complete mess. With books, torn paper, and thick file folders scattered around. But rather than paying more attention to the scattered objects, Heng more concerned about Rebecca's condition, which according to him was getting worse from time to time.

It didn't feel like he is with Sergeant Rebecca Armstrong—a cheerful and enthusiastic junior and co-worker. Rebecca who was standing beside him now is not much different from an undead walking around emotionlessly. It was like he is with stranger he had never met before. Something had made Rebecca turn into someone else he didn't recognize, at all.

Trying to muster up the courage, Heng opened his voice and spoke carefully, "Nong... if you're not feeling well, we can go outside to get some fresh air."

"Why should I do that?" without looking up, Rebecca answered.

"Just for a moment. After that you can come back in here and find what we need. Seng and the others don't seem to be done up there yet, so perhaps you could monitor the personnel on duty outside."

Rebecca considered for a moment, but decided to stay inside. Even though the fear and anxiety kept stifling her and still didn't leave her alone, she kept pushing against it all to move on. She no longer listened to Heng's answer and looked to the side, at a filing cabinet. Her gaze then dropped down to the barely visible black footprints of the cupboard feet.

When the cupboard remains in place and is not moved or shifted, the black trail should not be visible because it is covered by the cupboard. Since the black trail was visible to the naked eye, Rebecca guessed that the filing cabinet had shifted slightly from its original position.

Heng followed Rebecca's gaze. His irises fell on the black stains on the floor later, looking into Rebecca's face to read what she was trying to tell him non-verbally. He understood what he had to do next, especially when Rebecca started using the strength of her arms and body to slide the cupboard to the other side of the room and away from the wall.

There is clearly something hidden behind the wardrobe and it took the two of them to exert a concerted effort to slide the large wardrobe past the piles of books and scattered sheets of paper.

While Heng and Rebecca were struggling to move the cupboards, Seng, Irin and Noey trotted down the stairs to gather in the living room—Freen was there, standing and looking down with her eyes focused on the laptop screen. Seng approached, placed three bugs on the table before the three joined Freen who was watching CCTV footage on the second floor and the front door leading to the front yard.

From what Freen could see—of course based on the results she got after fiddling with the surveillance camera storage in Rebecca's house—the owner of the house had arranged that the camera footage would be deleted automatically after one month. She couldn't predict when all these cameras and bugging devices would be, but she hoped that all the CCTV footage left on the memory card and cloud storage would help her find the monster.

She opened the recordings one by one and checked them at 4x speed. She started on the record two weeks ago—which at the time, she was still working on her move from Chiang Mai so she was in Bangkok dealing with important paperwork. A busy day—A record from the existing surveillance camera overlooks the courtyard and front gate. It was night time, and apparently Rebecca happened to be outside the house as the gate was still locked tight.

Nothing suspicious in the first few minutes. Until Irin suddenly said while pointing at the laptop screen, "There is movement at the other end, a black shadow."

"Ghost?" Seng interrupted, at which point he was immediately rewarded by a small smack on the waist from Noey.

Freen stopped the video recording and zoomed in to the part Irin was pointing at. If you look more closely, you can see that a black shadow resembling a human body jumps down from the wall that borders the other house beside it. "It's a human," she muttered.

The video then resumes. This time they let the video move to notice the movement of a black figure that only appears for a few seconds before it goes out of camera range. Freen pressed the space button and played another video showing a different angle from the first video. The video came from a surveillance camera near Rebecca's front door—of course it showed the figure far more clearly than before.

As soon as possible Freen pressed the space button. "This is the person we are looking for," she said. She continued the video again to pay attention to the movements of a human figure dressed in black that appeared in the video recording. The footage is in black and white because it relies on night mode, but she can still see her clothes and stature from the waist to the top of her head.

The perpetrator was wearing black clothes—black pants, white and black sneakers, also a black hooded jacket complete with a white hat. Her face was covered by a black mask so that the camera could only catch a pair of sparkling eyes in front of the camera. The thing that surprised her was her brown hair which was tied up, then tucked inside a hat.

No, Freen couldn't believe this person was a man. Obviously her posture is different from men who generally have broad shoulders and height. If not, there must be at least one aspect that can indicate that the person she is seeing in the CCTV camera footage is a man. In fact, her long, light-colored hair and this posture of hers completely convinced her that she was a woman.

This was probably the only thing that left her speechless. The serial killer who terrorized Rebecca and killed three women over the last few months.

Her three comrades who were around her were equally shocked now. They had no idea that the perpetrator of the heinous murder they were looking for was a woman. Freen took the screenshot that most clearly showed the killer's facial features—the eyes, the shape of the face, and which showed the color and approximate length of the hair. She also rewinds the previous video to take a screenshot showing her body more clearly from head to toe.

She transferred everything to a spare flash drive, then closed the laptop and took it with her—she intended to take it all back to the office for further investigation. The laptop was then given to Seng for safekeeping. So the man who was asked for help jogged towards the exit, Freen, who began to notice the absence of someone who should have been there, couldn't stop herself from walking here and there—searching for her whereabouts.

"Where is Sergeant Armstrong? She should know this," Freen hissed as she pushed open several doors of the room with her left hand. She was just about to push harder on the last door if it didn't open by itself when her fingertips barely touched the surface of the door. The door opened, and two humans who seemed to have torn apart the room immediately appeared before their eyes.

Heng, who initially froze when she heard the sound of Freen's shoes, suddenly turned his head with a tense expression still clearly visible there. Immediately, Freen stepped forward and shifted Heng's body away from the wall and wardrobe that were no longer in its original position. Now, she understood why the tall man froze in front of the wall with Rebecca walking away while ruffling her hair with meaningless growls.

The wall in front of her... had been stained with red paint with the letter S. The fourth letter that became part of the next three letters.

ARM and S, become ARMS.

Relaxing the hands that she originally kept in a clenched position and now moving to touch Rebecca's shoulders with one gentle touch, Freen tried hard to avert her eyes from the wall to Rebecca who was leaning her head against the window pane. "Sergeant." She called her.

Rebecca looked up—oh, Freen could see clearly how those vacant eyes stabbed something into her heart. How could a single person's light just disappear like this?

"Heng, please monitor the officers working outside. I will settle things with Lieutenant Chankimha here." Rebecca ordered. The woman bent down, picked up some of the books on the floor and placed them on the table. Knowing that Heng was still in place, the young sergeant was forced to reconfirm. "Why are you still standing there? Didn't I give you an order?"

"But—" Heng answered, but he quickly covered her mouth again and chose to remain silent and glanced at Freen.

As if understanding what was going through his mind, Rebecca continued, "It's not like I'm going to pull out my gun and shoot her in the head here, Heng. No matter how much she annoys me, I wouldn't have killed her that way. So hurry up and get out of here so we can sort this out."

He wanted to retaliate, but who is he when Rebecca had given him an absolute order? Technically, Rebecca is his superior and as the police who upheld a system of hierarchy and respect, Heng had no right to refuse his superior's orders unless he wanted some kind of punishment. So with slightly drooping shoulders, Heng turned to leave and closed the door of Rebecca's work room.

Turning her attention away from the closed door, Freen let out a light laugh as she turned to Rebecca. "Shoot me, you say? So you want to kill me now? Nice, but I don't like the idea of killing with a gun. Too messy. The blood can be splattered anywhere and troublesome for the cleaners at the crime scene. I've seen countless people die in all kinds of ways, all kinds of injuries, and all kinds of... weapons. Shooting with a gun is too classic and I don't want bits of my brain sticking to the ceiling either, so you might need a little reference from me if you want to kill me."

What the hell? Rebecca was wide-eyed. Completely unable to hide the look of surprise on her face when she heard Freen's words that sounded terrible in her ears. "You are crazy, Sarocha."

"Indeed, I am," frowning and returning to the cold expression that Rebecca hated the most, the taller woman took several steps towards Rebecca that forced the other woman to step backwards until she hit the wall. "And you're brave enough to bring out your only savior when you know you're about to be trapped with someone like me, alone, in this closed place."

Rebecca took a deep breath, glancing at her gun which was on the table. It was quite a distance from where she was cornered now. But if she moved fast enough under pressure, she could push Freen away and get her gun back. "If you dare to touch me, I will shoot you."

Following Rebecca's gaze, Freen stepped back and slowly exhaled. A small smile suddenly appeared on her face as she took the young Armstrong's revolver and cradled it in her hand before touching the end of the barrel and holding it out to Rebecca. At first, she seemed hesitant to accept it. But because Freen raised an eyebrow at her—as if wondering why she didn't grab her belongings right away—Rebecca finally took the gun back and quickly secured it.

Freen scratched the back of her neck that didn't itch. Now, with a more flexible posture and expression than before, she said, "You're careless. Never leave your gun carelessly. It could be bad if someone snatches it and puts your position in danger."

"You're one of the people that put me in danger, I think." Rebecca walked past Freen and she was now near the door.

"Hey, I'm kidding, okay? Don't take me too seriously, it could hurt your heart and make your mind in a mess."

"I'm sure you have something you'd like to tell me."

Freen muttered the word okay, and she turned back to face the wall that was crossed out with the letter S. She took out her cell phone and took a few pictures. "We found out who the person who terrorized you was and... she was a woman which I also didn't expect that a woman could do something this terrible," Freen's words made Rebecca raise her head, "Listen, I have an acquaintance who is a criminal profiler. We can make assumptions about the modus operandi and predict what the killer will do next, but perhaps not as accurately as profilers who are more skilled in this field. How? You want me to contact her?"

"The sooner the better, Lieutenant." Rebecca muttered. She lifted her chin at the wall in front of her, "The problem is, she already has a target. It seems that what you told me is no longer an assumption, but a late fact."

"I already know that." Freen answered briefly before she stepped out with the phone in her hand. Before leaving, she pointed at the wall in front of Rebecca and out the window alternately.

Rebecca nodded and Freen disappeared from her sight. She picked up the cell phone on the table, then looked through Nam's contacts. She needs to tidy up and clean her house from other traces that might have been missed, so she needs forensic assistance.

It didn't take long for the doctor to answer the phone, and as soon as her loud voice was heard, Rebecca without giving her the chance immediately attacked her quickly, "Nam, I will tell you the progress of the case and you tell me the progress of the autopsy. Deal?"

"Huh? Yes, of course. Alright, hurry up and say it."

"We searched my house and we found lots of traces left by the killer. She was also caught on the CCTV camera and now Freen is contacting the profiler while the others are securing the footage and questioning local residents. There is a scrawled S in my study, I thought it has something to do with the next victim so I thought to ask your team to come."

"We really need each other, don't we?" taking a moment to laugh out loud with her hoarse voice clearly indicating that she had not slept well in days, Nam continued, "By the way, Becky... regarding the autopsy results and this case, you should probably consider bringing your family back to England before it is too late."