Last year I read about a movie that I'd like to watch now, but forgot the name. Facts:
- from late 70s or early 80s
- murder mystery, psychological thriller
- about a woman who was found dead （maybe in the lake?）and there is only one witness who is interrogated by the police
- very long film, 3h or maybe even 4h long
I remember that the movie had several （2-3）reviews on imdb and there was somebody sitting in the darkness on the cover art （and cover art was black and white）.