It’s a plot twist not even Alfred Hitchcock would think of.

The elderly Brooklyn woman found this month living with the skeletal remains of her son, possibly for as long as 20 years, is a legally blind hoarder who may not have even known he was there, NYPD sources said.

The chilling discovery of the skeleton was made Sept. 15 when a relative showed up at Rita Wolfensohn’s Midwood home to fetch her belongings and take them to her in the hospital.

In a debris-choked second-floor bedroom, sister-in-law Josette Buchman found a “completely intact” skeleton, dressed in jeans, socks and a shirt, lying on its back on a thin mattress on the floor, police sources told The Post.

“It’s like some reverse ‘Psycho’ scene,” a law enforcement source said at the time, referring to Hitchcock’s 1960 horror flick in which a son, Norman Bates, keeps his dead mother’s remains in a basement.