Originally Posted by
Wraith
As such, they probably have contemporary knowledge of Imperial culture, up to and including employing their own Astropaths and Sanctioned Psykers. The easiest why to find out if someone is a Psyker is just to have another, confirmed Psyker look at them - get a lineup of suspected witches once every ten years or so, have your "Court Magician" look 'em over and send away the ones that are just mutants or otherwise unlucky enough to be picked up by the local PDF/Militia/Whatever.