As an example of just how low the budget of this film was, when a note is delivered to Mr. Wong's front door, the actor playing the messenger has no dialogue. If the actor had spoken even one word, SAG rules would have required Monogram Pictures to pay him an additional $10!
This was the first of five films in which Boris Karloff played Oriental detective Mr. Wong. These films were essentially Monogram Pictures (a "Poverty Row" studio) attempting to knock off of Fox's popular "Charlie Chan" franchise. it is interesting to note that Karloff had co-starred with Warner Oland in Fox's Charlie Chan at the Opera (1936).
The film's copyright was not renewed and it is in the Public Domain.
This film can be found on many multi-film horror collections on DVD because of its star, Boris Karloff.