439

```

Click—

The tightly closed smart lock was unlocked, and the tall, bald man pushed open the door.

The dark, tidy interior of the house appeared before the man.

The man did not turn on the light but took out a flashlight and turned it on, its strong glow illuminating the room.

He reached out to close the door and looked around with the flashlight in hand.

The house was neat; the floor was dust-free, clearly someone had been living there regularly.

He walked to the front of the sofa, crouched down, and examined the freshly polished floor, where a carpet should have been, but now, there was nothing.

Soft sounds came from the ceiling, the noise of the house's ventilation system at work.

The man lay on the ground, inspecting the floor carefully with his flashlight.

He inserted his fingernail into the crevice of the floor, scratching out fine red granular substances. He collected these particles and then carried on deeper into the house.