So this kind of mechanical, non-technical physical labor often has another characteristic: that is, the working hours are very long.
These people, their social circles are generally not too large, nor are they very fluid.
Because both mobility and social interactions require an investment of time, energy, money.
This characteristic is very important!
It can even be said to be the core idea in case-solving.
The reason is simple.
For victims with a narrow social circle, the fact that they were all killed by the same murderer suggests that there is some overlap in their characteristics, such as the killer being an intermediary that specifically hires cheap labor, or the killer specifically hunting these overlooked lower-class individuals in a poor area...
In any case, the killer must have targeted these low-class victims due to some specific factor.
Finding this specific factor means we can lock onto the killer's identity!
So how do we find this specific factor?
