The D.A. is a half-hour courtroom drama that aired Friday's at 8:00pm from September 17, 1971 until January 7, 1972 on NBC. Somewhat similar to the theme of Law and Order, The D.A. followed investigators that investigated a crime in one segment of the show, and then followed prosecutors prosecuting in the second half of the show. In this case, though, Deputy D.A. Paul Ryan (Robert Conrad) lead both the investigation and the trial work. Most cases found D.A. Ryan opposite Public Defender Katherine Benson (Julie Cobb).