What are the most promising technologies to aid in the detection of predators?

[icumara]

I originally posted this question on the Psychology and Neuroscience stack exchange but am reposting here in full to respect the rules against links on this forum.

Some human beings appear to be “without conscience” in that their actions in the world appear to be unrestrained by genuine care and concern for the well being of other human beings.

Some of these individuals are exceptionally skilled at gaining the trust of others while hiding their true motives.

What are the most promising technologies to assist with the detection of these predators?

I am currently aware of 4 but it is unclear to me how effective any of these actually are currently or have the most potential.

1: genetic testing
2: Magnetic resonance imaging (MRI)
3: Facial Action Coding System (FACS) (perhaps aided by Artificial Intelligence)
4: reputation systems

This problem is complicated by the fact that there seem to be a number of different, and perhaps unrelated, conditions that might be responsible for the non-emergence of a conscience.

For example, the HARE checklist would seem to be a good tool for detecting psychopathy, but perhaps not for Narcissistic Personality Disorder (NPD).

Bonus points if the technology holds the promise of actually being easily used by any individual in the population at low cost in the near future. For example, an AI supported FACS and reputation system in a mobile app or augmented reality (AR) system.