A young writer, Bernard (Peter Baldwin), returns to the small town where he had vacationed previously, He goes to visit Tilde (Virna Lisi), a young woman with whom he had a brief sexual relationship; however, she isn’t there and the locals are not keen on talking about why. Bernard learns that she has been killed and her body was thrown into the lake. The writer presses on in his investigations and as he goes through the town, casual encounters build up an atmosphere of menace… –filmaffinity.com
Luigi Bazzoni (25 June 1929 – 1 March 2012) was an Italian director and screenwriter. Born in Salsomaggiore, Bazzoni was the elder brother of the film director and cinematographer Camillo Bazzoni and a cousin of the Academy Award winner Vittorio Storaro. He began his career as assistant director of Mauro Bolognini. Later he became director of films and short films, gaining critical attention for two spaghetti westerns, L’Uomo, l’orgoglio, la vendetta and Blu Gang – Vissero per sempre felici e ammazzati. His short film Di Domenica achieved a Special Mention at the 1963 Cannes Film Festival. —Wikipedia
One of the most impressive pre-Argento gialli I've seen. I've heard it described as "Last Year at Marienbad with a more straightforward narrative." That's not far off, with the editing (especially in the first 30 minutes) providing a disorienting, elliptical vibe inside the walls of the cursed hotel (an effect that seems like it must be a result of Questi's influence on the script). Just outside my giallo top 10.