Edward G. Robinson Jr. was originally cast in the movie but was fired by the producers following his arrest for writing a bad check for $138 to a Laguna Beach garage.
Curt Siodmak considered interchanging the Raymond Burr and Lon Chaney Jr. roles, but because of Chaney's deteriorating looks, the idea was dropped.
Raymond Burr reportedly took an immediate dislike to Lon Chaney, according to Chaney biographer Don Smith.
Although it only took seven days to shoot the movie, Lon Chaney Jr. was scheduled to go on a ten-day publicity tour on behalf of the film, which eventually grew to 4-1/2 months, according to Chaney biographer Don Smith.
Shot in 10 days.