Marg Helgenberger to leave "CSI"

Actress  Marg Helgenberger, who has been with "CSI: Crime Scene Investigation" since  it began 11 years ago, is quitting at the end of this season.The 56-year-old Helgenberger, who investigator Catherine Willows played on the show, told reporters gathered in California for the annual fall TV previews they plan to leave at the end of the upcoming 12th season of what CBS is calling the most watched