 The house where the final "drowning" occurs is the same house and  pool used in the pilot for _"Rockford Files, The" (1974)_ (qv)  (_Rockford Files, The (1974) (TV)_ (qv)/"Backlash of the Hunter")  and in the later Columbo episode  _Columbo: The Most Crucial Game (1972) (TV)_ (qv).