Robert Halderman

David Letterman's blackmailer Robert Halderman is out of a New York City jail after serving four months behind bars. The former CBS News producer got two months knocked off his sentence for good behavior. Halderman pled guilty to extortion after demanding $2 million from Letterman to keep quiet…

David Letterman's extortionist is headed to the slammer -- Robert Halderman was just sentenced to six months behind bars for trying to squeeze $2 million out the "Late Show" host. Halderman -- who pled guilty to attempted grand larceny back in March -- just appeared in Manhattan Criminal Court in…