Curneth was a tracer for the Ramuran government. In 2374, he was sent to capture Kellin, a former tracer who had sought asylum aboard USS Voyager because she fell in love with Chakotay on her previous mission.
During an attack on Voyager, Curneth transported himself aboard, undetected because of his personal polarization cloak. When Kellin detected his presence, he immediately shot her with a neurolytic emitter, which wiped out all memories of her interactions with Voyager. Chakotay placed Curneth in the brig and demanded that he reverse the process, to which Curneth replied that he had neither the knowledge nor the intention to do so. Since Kellin no longer remembered why she wanted to stay on Voyager, Curneth was allowed to return to Ramura with her. (VOY: "Unforgettable")