Orta was a Bajoran terrorist (or freedom fighter).
Orta was captured, interrogated and tortured by members of the Cardassian Union. His torture included the severing of his vocal cords and, as a result, Orta was forced to use an embedded voice synthesizer in his neck for the rest of his life. Eventually, he became the leader of a group of Bajoran terrorists.
Later, in 2368, the Cardassians tried to frame him for an attack on a Federation colony. The Cardassians were hoping to manipulate the Federation into eliminating the Bajoran terrorists. The plot was exposed when Jean-Luc Picard and Ro Laren discovered that Orta did not have the resources to carry out such an attack. (TNG: "Ensign Ro")