I think James Mason is brilliant and he’s the star in the 1947 thriller, The Upturned Glass.
He plays Michael Joyce, a brain specialist who falls in love with Emma Wright (played by Rosamund John).
That’s the two of them in the lead image.
Both are already married to other people and before the relationship gets off the ground, they part.
Emma falls to her death from an upstairs window and although it’s not treated as murder, Michael Joyce suspects otherwise and investigates further himself.
He ends up pushing Emma’s sister-in-law to her death from the same window, as he becomes judge, jury and executioner after working out that she committed the murder.