Li Yu had just installed six surveillance cameras on the outer wall of the inn, covering all directions and angles and even encompassing a nearby street and two alleys.
In addition, during his last return, he had purchased some wireless eavesdropping devices and brought them along this time. These devices, similar to radio stations, could operate on specific frequencies to send and receive information without the need for an internet connection.
The disadvantage was that their sound pickup radius was only about one meter, making it hard to hear from farther away; however, Li Yu used them to monitor the movements inside nearby buildings, exploiting the targets' ignorance of modern eavesdropping technology.
He even had people present these devices as gifts to the suspects, claiming they contained some form of lucky power.
Many people treasured them as precious items, strung them up with cords, wore them around their necks, and refused to take them off even while sleeping.
