Man, was it Cardassians? Huh, I could have sworn that it was Romulans. Star Trek has so many nearly identical alien races that it's impossible to keep them straight.You're thinking of Seska I think, and she was a Cardassian who had been surgically altered and embedded in Chakotay’s cell of the Maquis. And it was the Kazon she ended up throwing in with.
But yes, the Kazon were who I was talking about. The first of Voyager's stupid and warlike alien races that inexplicably possess and maintain technology capable of interstellar travel. Voyager really is in love with that concept, also see the Hirogen, a race of hunters that would surely have either died out due to infighting or have been eliminated by the surrounding galactic community as being a hostile threat.