Nimira was the Chief Examiner of the Mari, a race of telepathic beings whose society was almost free of violent crime. She was one of the last constabulary officers in this virtually crime-free society. She and Tuvok became friends. Both respected the way their respective societies eliminated violence. He asked her to visit USS Voyager, and she accepted.
B'Elanna Torres had bumped into a Mari citizen, setting off a pattern of violent behavior among two Mari citizens. Shortly after, Nimira arrested Torres for violent thoughts. She intended to use an engramatic purge on Torres, which could cause brain damage, in order to remove her violent thoughts.
Tuvok, suspicious of the violent behavior of the Mari, mind-melded with Torres and found out that a man named Guill had probed her mind. It was discovered that Guill was a dealer in a black market of providing violent imagery among the Mari. Nimira was at first reluctant to accept the evidence, but when Guill admitted his guilt after Tuvok inflicted pain on him through a mind meld, she agreed to take him into custody and to release Torres. (VOY: "Random Thoughts")