Glinn Lasaran was a Cardassian informant for the Federation in 2374, during the Dominion War. After two months, he became concerned that he was drawing suspicion from his Vorta adviser, and saw his last opportunity to escape in an assignment to the Dominion base on Soukara. Lasaran contacted Starfleet and requested that he be extracted, in exchange for providing information on the number and activities of every Founder in the Alpha Quadrant.
Lieutenant Commanders Worf and Jadzia Dax were ordered to retrieve Lasaran, but after they infiltrated Soukara, Dax was injured by a Jem'Hadar patrol. Worf chose to abandon the mission rather than have her die. Lasaran was killed trying to re-enter the Soukara base. (DS9: "Change of Heart")