In the TNG episode 'The Mind's Eye' Geordi was replaced by an impostor that was sent to Risa in his place. This individual looks very similar to Geordi (human, male, black, similar height, build, etc) so how have the Romulans come into cooperation with such a person?
Did he make any other appearances elsewhere? Are there any other sources (such as the novels) that can shed some light on his identity? Was he a hologram, a human replica, an android or something else entirely?