A telepathic humanoid society that has outlawed violent thoughts, treating them as crimes to be detected and purged.
The Mari are a peaceful telepathic people in the Delta Quadrant who have eliminated violent behaviour from their society by making even violent thoughts illegal.
In Random Thoughts, B'Elanna Torres was arrested after a moment of anger was telepathically picked up by a Mari citizen, who then committed an assault. Tuvok's investigation, opposed by Chief Examiner Nimira, uncovered a black market in which a Mari named Guill was trading in forbidden violent thoughts, clearing Torres before an engram purge could harm her mind.