https://www.youtube.com/watch?v=3DvYRoiP_p8
http://www.imdb.com/title/tt0064310/reference

"This offbeat potboiler from Psycho scripter Joseph Stefano involves a plot hatched by mod couple Wylie (Michael Sarrazin) and Kassia (Gayle Hunnicutt) to murder Wylie's wealthy, cat-loving aunt Danny (Eleanor Parker). There's only one hitch in their scheme, but it's a doozy: Wylie suffers from a severe case of ailurophobia -- an irrational fear of all cats. In order for their plot to succeed, the pair must first eliminate Aunt Danny's legions of feline companions...which turns out to be much more difficult than expected, thanks to a sly, deadly counter-plot."