Joe Halderman, the U.S. television producer who pleaded guilty to blackmailing David Letterman for $2 million, is now working for \"On the Case with Paula Zahn.\" Halderman served four months of a six-month jail sentence last year for trying to extort money from the late-night comedian in exchange for his silence regarding affairs the married Letterman had with female members of his staff. Halderman also was placed on five years probation and ordered to complete 1,000 hours of community service after pleading guilty to grand larceny. The job with \"On the Case\" marks the beginning of his professional comeback. \"On behalf of \'On the Case\'s\' production team, we have been impressed with Joe Halderman\'s professional accomplishments as an Emmy award-winning producer for \'48 Hours\' and CBS News,\" producer Scott Weinberger said in a statement to the New York Daily News. \"With the network\'s prior approval, the team has brought Halderman on as a producer for \'On The Case.\' We are confident that Halderman will make significant contributions to the success of our award-winning investigative newsmagazine.\" The Daily News said Halderman\'s exact job title has not yet been announced. The weekly program \"On the Case\" airs on Investigation Discovery.