Gaslight (1944)

In George Cukor's dramatic mystery-thriller, based on the 1938 play by Patrick Hamilton:

• the scene of the early train journey by Paula Alquist (Ingrid Bergman) to Lake Como, when she conversed with Miss Thwaites (Dame May Whitty) in a compartment - the garrulous Englishwoman loved murder mysteries, and was reminded of the 'real, live murder" that occurred in Paula's murdered aunt's London home ten years earlier: "It was a most mysterious case. They never found out who killed her. They never even found a motive"; the tragic recollection of the unsolved murder case where her Aunt Alquist was murdered was un-nerving to the meek and disconcerted Paula
• the domination and slow destruction of wife Paula Alquist Anton's (Ingrid Bergman) sanity by her manipulative and greed-obsessed but charming husband Gregory Anton (Charles Boyer), during his surreptitious search for her aunt's valuable jewels, where they now lived in the London house - the ancestral home at 9 Thornton Square - that she had inherited from her dead aunt
• the scene of Paula's discovery of an incriminating piece of evidence - one of her aunt's old letters inside a score, written by her aunt's murderer (Sergis Bauer) two days before the homicide; Gregory violently snatched the letter from her hands
• Gregory's flirtations with young, teenaged Nancy Oliver (Angela Lansbury in her film debut), the recently-hired house-maid, to slowly, menacingly, and seductively drive his innocent young wife mad; in Paula's presence, he flirted with the maid (about her beat-policeman boyfriend) and suggested that the cheeky young girl help restore his wife's youthfulness: "I was wondering whether you might not care to pass some of your secrets on to your mistress and help her get rid of her pallor"
• the beginning of Gregory's ploys to make Paula go crazy, including a missing family heirloom brooch in her purse, gaslights mysteriously dimming, footsteps from the third floor attic above, a missing framed picture (causing Paula fears that she was a kleptomaniac), etc., and her feelings of panic: "I hear noises and footsteps. I imagine things, that there are people over the house. I'm frightened, and of myself too"
• the search through Paula's purse at the Dalroy's musical concert party and the discovery of Gregory's missing pocket watch in her handbag - causing Paula's serious breakdown when they returned home; Paula asked: "Gregory, are you trying to tell me I'm insane?...But that's what you think, isn't it? That's what you've been hinting and suggesting for months now, ever since the day I lost your brooch. That's when it all began. No, no, no, it began before that. The first day here when I found that letter" - but he denied that the letter even existed
• in the ultimate conclusion, suspicious Scotland Yard detective Brian Cameron (Joseph Cotten) searched through Gregory's locked desk with Paula, where the letter from Sergis Bauer ten years earlier was hidden away: "I was right. There was a letter...I found this. But my husband said I dreamed. And now it's here. It's been here the whole time"; it clearly revealed that Gregory (aka Sergius Bauer) had in fact murdered Paula's aunt in the same home located at Number 9 Thornton Square in London, England
• Cameron assured Paula: "You're not going out of your mind. You're slowly and systematically being driven out of your mind"; he had become convinced that Gregory spent his nights methodically hunting and searching through her aunt's possessions in search of her missing jewelry

Cameron: "You're not going out of your mind"	Vengeful Accusations Against Husband

• Paula's final scene of psychological retribution - including her vengeful and scornful statement against her husband, who was tied by rope to a chair: "If I were not mad, I could have helped you. Whatever you had done, I could have pitied and protected you. But because I am mad, I hate you. Because I am mad, I have betrayed you. And because I'm mad, I'm rejoicing in my heart, without a shred of pity, without a shred of regret, watching you go with glory in my heart!"