The Mari are a telepathic humanoid species from the
Delta Quadrant. They were a violent species. Crime was a huge issue on their
planet.
To solve the problem, the Mari outlawed violent thought
and developed a memory technique. This technique removed offending engrams from
a criminal's mind.
Although violent thoughts had been thought to be
eradicated, a black market and violent thoughts were sold. The culprits were
caught and the black market was discovered.