Friedkin, who directed such films as The Exorcist and The French Connection is profiled in the July 1998 issue of the British film magazine Sight and Sound where he is referred to as an "agnostic Jew". The article is called 'Lucifer Rising: The Exorcist Returns' and concerns the 25th anniversary of one of the most famous horror films.
From the article (Page 8): In the quarter century since its opening, The Exorcist has been remembered less as a complex metaphysical drama than as a terrifying tour de force. Yet for all its shocking power, the film is an unsolved riddle, a masterful amalgam of contradictory themes that maintains a tension between the divine and the depraved, the progressive and the regressive, the hidden and the apparent. Written by a devout Catholic (William Peter Blatty) and directed by an agnostic Jew (William Friedkin), The Exorcist managed simultaneously to enthral and appal Americans who had lived throught Manson, Vietnam and Watergate, and to capture the imagination of thousands of Europeans for whom Pope Paul IV's 1972 address regarding the "question of the Devil and the influence he can exert on individual persons" was recent news.