Joan Crawford supplied her own wardrobe for the film, with the exception of the leotard, which was designed by Edith Head.
Joan Crawford was asked by producer Herman Cohen not to drink alcohol during filming. She informed Cohen that she was "just a sipper", but she respected his wishes.
As Superintendent Brooks is talking to Commissioner Dalby after one of the mysterious deaths, they pass an ad that says "Come Alive! With Pepsi". Joan Crawford was the widow of Alfred Steele, who had been CEO of the Pepsi-Cola Company, and at the time of filming, Crawford was still on the Board of Directors. Product placement of Pepsi can be seen in other Crawford films of this era, including
Strait-Jacket (1964).