The weapon by the pillow

"The police...weren't they here? Why haven't they made a sound?"

The lynx, pressed against the hole in 403, listened intently to the sounds outside, its face filled with confusion and unease.

"Perhaps... they're deploying? Or... they've encountered some obstacles?"

Shadow listened intently for a moment, then looked at the key and hairpin found on Liu Li's body in his hand, and suddenly whispered:

"Something's not right. If the police arrive, they usually try to calm the situation down before considering breaking down the door. This complete silence... is not normal."

"Could it be...not a police officer?"

Li Kai gritted his teeth: "Regardless of whether it is true or not, we can't just wait! Keep searching this room! Liu Li died here, the murderer might have left clues! And what is this key for?"

"Everyone, wait a minute!" Cheng Tan forced himself to pull himself out of his daze at the unusual scene outside the door.

"Our most important step is to preserve the crime scene as much as possible! Because..." He pointed to Liu Li's body, "someone died here, and we are all suspects! At least... to the police!"

"He's right! Everyone, take photos and videos first, and try not to touch these things!" Lin Qian frowned. "But we've already damaged them... Never mind that for now, we need to preserve the current scene!"

"What Li Kai said earlier makes sense! We can't rely on outside help anymore, at least not now. We have to save ourselves, we have to find more clues." Cheng Tan's gaze fell again on the overturned stool next to Liu Li's right hand.

Besides the drag marks and kicking marks, there seemed to be some other marks on the dust.

He crouched down and carefully shone the flashlight on the object.

Something's not right... It looks like there are marks made by fingers or something?

But it's not a word, it's more like... a simple line drawing?

He moved closer to examine it more closely.

It looks like a... rectangle? There's an X drawn inside?

Next to the rectangle, there are several crooked arrows pointing in different directions.

"Come and see this!" Cheng Tan called to the others.

The crowd gathered around.

"This is... a drawing Liu Li made before she died?" Lin Qian frowned. "What was she trying to tell us?"

"A rectangle... an X..." Li Kai pondered, "A room? This room? Does the X represent... a mistake? Danger? Or... the target?"

"Arrows..." The shadow looked in the direction of the arrows. One arrow pointed to the east wall of the room adjacent to 405, one pointed to the ceiling, and another... pointed to the ground.

"Could it be..." Wu Wenbin suddenly remembered something, "My father's survey map! On that map, besides the anomaly point of 403 itself, did you mark the structure of the adjacent rooms at the locations circled in red? Especially... the thickness of the shared walls?"

Survey map!

Cheng Tan suddenly remembered the notebook that Wu Wenbin had brought!

His father, Wu Guodong, may have surveyed more than just 403 back then!

"The blueprints! Quick, take a look at the blueprints!" Cheng Tan said urgently.

Wu Wenbin immediately took out the plastic file bag from his canvas bag again, took out the yellowed survey map of Room 403, and carefully spread it out on the dusty floor.

Under the flashlight beam, the lines and markings on the drawing became clear.

Cheng Tan, Li Kai, Yingzi, and Lin Qian all crowded around to take a closer look.

On the drawings, besides the interior structure of room 403 and the red pen markings, there are indeed some simple markings and dotted lines about the adjacent houses on the edge of the drawings.

吴文斌指着图纸边缘一行小字念道：「『东侧墙（与405相邻）实测厚度28cm，西侧墙（与401相邻）实测厚度26cm，南侧墙（外墙）厚度……北侧墙（与402相邻）……』」

He stopped.

Because on the drawings, the thickness markings for the north wall are not followed by numbers.

Instead, it was a question mark drawn very thickly in red pen.

Next to the question mark, there is a line of even smaller text:

"There is an abnormal echo zone in the middle of this wall, and the thickness seems to be uneven, with the thinnest part estimated to be less than 30cm, suggesting the presence of a layer or cavity. Further investigation has not been conducted."

Interlayer or cavity!

"Less than 30cm..." Shadow immediately stood up, walked to the edge of the hole they had just smashed, and measured the thickness of the wall with his hand. The exposed brickwork at the edge of the hole was clearly thinner than a normal wall!

"This wall really does have a hidden layer!" Shadow said in a deep voice. "But where is it? We broke through the solid part; the hidden layer should be somewhere else!"

Cheng Tan looked at the simple line drawing of a rectangle and a cross left by Liu Li on the ground, and then looked at the question mark and "abnormal echo zone" marked in red on the drawing.

Rectangle... Cross...

He suddenly looked up and shone his flashlight on the north wall of room 402—the wall that was adjacent to room 401.

"Not this wall!" Cheng Tan's voice trembled with excitement. "The 'rectangle with an X' that Liu Li drew might not refer to this room! It might refer to... the mezzanine space next door! That 'X' might mark... something in the mezzanine! Or, the entrance!"

He pointed to the north wall of room 402: "The unusual echo zone, the mezzanine, it might be in this wall! Or, it might be over there in room 401! Before Liu Li died, she wanted to tell us the real secret hiding place!"

"401?" Li Kai frowned. "Who lived in 401 back then?"

no one knows.

"Whoever it is, the hidden compartment might be there!" Cheng Tan looked at the small key he had found in Liu Li's hand. "Could this key be the key to opening the hidden compartment?"

"Find the entrance!" Without hesitation, Li Kai rushed to the north wall of room 402 and began patting it to find the hollow sound.

The others immediately sprang into action, their flashlights sweeping up and down the north wall of room 402, accompanied by a series of tapping sounds.

The wall was an ordinary white-gray wall, already mottled and covered with cracks and stains, and looked nothing special.

But with the experience of 403, no one dared to let their guard down.

"Here!" Lin Qian suddenly called out, standing next to an old wooden wardrobe near the corner of the wall.

The wardrobe was right next to the north wall and was quite old; the doors couldn't even be closed properly.

She shone her flashlight on the seam between the wardrobe and the wall: "Look, the dust here... it looks like it's been wiped off. It's very new."

Shadow stepped forward and examined it closely. Indeed, the dust on the side of the wardrobe against the wall was noticeably thinner than the surrounding area, and there were fine, regular friction marks, as if someone had repeatedly pushed and pulled the wardrobe.

"Behind the wardrobe?" Li Kai and Cheng Tan immediately stepped forward and tried to move the wardrobe.

The wardrobe was heavy, and it seemed to be stuffed with things inside. It took the three of them working together to move it about half a meter.

The wall behind the wardrobe was exposed.

At first glance, it looks no different from other places.

But Shadow crouched down and shone his flashlight almost against the wall to carefully examine the seam between the base of the wall and the floor.

"There's a gap," he whispered.

At the base of the wall, about ten centimeters high, there was an extremely fine, straight horizontal crack, about sixty centimeters long, almost parallel to the floor, which was almost invisible without close inspection. The crack was very neat, clearly not a natural crack.

Shadow carefully inserted the thin blade of a multi-tool into the crevice and gently pried it open.

"Click."

A soft sound.

A wall panel, approximately 60 centimeters long, 30 centimeters high, and about 2 centimeters thick, suddenly popped open inwards with a crack!