You got it.
I’m half joking, it’s almost impossible to know the exact percentages. Personally, I believe, for the NYPD, it’s very high — judging from the sheer number of undercover officers that I recognize that I also think are psychopaths. Also being an undercover officer would be very attractive to psychopaths.
Recognizing undercover police officers is on a need-to-know basis. If you need to know, you will gain the ability to recognize them. Basically, cops pay attention differently than others, also their intent is always different. For example a crazy person standing and staring into the sky has one intent, a cop standing and staring into the sky in exactly the same position has another, namely the intent to look like a crazy person.
These cues are very subtle, too subtle for someone without the need to know to pick up. One can’t be trained to do so, but one can learn to.
The subconscious mind is much more powerful than the conscious mind. I’m not making this up. Scientists Prove that Your Brain is Actually Smarter Than You Are.
No psychopath should ever be allowed to join any police force.