Why? Because I would assume that my opponent was planting evidence to slander my people, and if I thought that they would act on hints and slanders well - I'd have a fun program of hinting and slandering the keystones of their operations (especially counter intel) as well as I could identify them.
The dominant game here is to trust your operation. The way that you win is to build as capable a trust system as you can thus enabling you to run as large an operation as possible. This is why terrorist networks operate in atoms, they are short duration by definition because they tip their hands with any action so there is no deep network building.
At work I often struggle to understand the motivations of some of my less benevolent colleagues, and this gets me into difficulty from time to time. But, the thing about the Chinese shooting the fella in the office carpark, to me, it doesn't sound like an act that is likely to forge deep bonds in the team.
do you have any reading on this?
This is pure conjecture.
It is quite easy to do data mining on your subjects if you aren't actually bound by laws, evidence, or human rights.
The drug lords were using AS/400 mainframes decades ago to ferret out traitors. Sure, they killed a few people who weren't, but, meh, who cares, right? I can't imagine the Chinese government actually cares to any greater degree.
Unless an informant doesn't actually want any tangible benefit, there is going to be SOME trail in the electronic ether nowadays. Even the act of disabling your phone is going to be a trail nowadays.
If you simply kill off anybody who falls afoul of your "standard profile" you're going to get your intelligence agents.