As a former assistant to David Letterman, Stephanie Birkitt had been the subject of national attention before. The 34-year-old New Hampshire native taped more than 200 segments for The Late Show from 1996 to 2008 — including interviews with Survivor castoffs and reports from the Winter Olympics. But when Letterman announced on his show on Oct. 1 that he'd been the victim of an $2 million extortion attempt, Birkitt found herself in a different — and much less flattering — spotlight. According to Letterman, Birkitt's ex-boyfriend, a CBS News producer named Robert (Joe) Halderman, tried to blackmail him by writing a screenplay, based partly on a diary of Birkitt's, about the wealthy and now married talk-show host's habit of seducing female staffers. Since the alleged plot was revealed, Halderman has pleaded not guilty — he claims it was an aggressive business deal gone awry — and the media have yet to hear a peep out of Birkitt, who may be trying to stay out of the limelight for good.