Shooting lasted July 7-21 1942, released October 22. This completed Boris Karloff's six-picture contract with Columbia.
The plot of this film has strong similarities to Arsénico y encaje (1944), in which both Boris Karloff and Peter Lorre were previously associated - Karloff appeared in the theatrical original (and at least three television adaptations) while Lorre co-starred in the film version.
This is the second of four film teamings of Boris Karloff and Peter Lorre, all of them comedies. Others were El rey del pánico (1940), El cuervo (1963) and Comedia de terror (1963).
Jeff Donnell is credited specifically with a "Miss" in front of her name. She was born Jean, but took on the nickname of Jeff as a youth because she loved the "Mutt & Jeff" comics.
A character makes reference to the Quiz Kids. This was a popular radio program in the 1940s that featured young geniuses.