This movie is a B-detective series film. This means that as a "B" movie, it was the second and usually lesser film on a double-feature bill. This didn't mean that B meant it was a bad film, but it was certainly given a smaller budget and had lesser pretensions and expectations from the studio. Many B-films were detective series films and they provided great but also relatively predictable entertainment (much like a movie version of a TV show like MURDER SHE WROTE or even LAW AND ORDER). Common to all these films were goofy or evil supporting characters, a very fast pace, a relatively short length (55-70 minutes) and a certain familiarity with the main characters. Some notable examples are the Sherlock Holmes, Charlie Chan, Falcon or Saint series films.
The Lone Wolf is in many ways particularly like The Saint or Falcon films because the lead (Warren William) plays a reformed thief and gentleman who is smooth with the ladies. While he's very easy to like and is obviously a force for good, the police never seem to understand he's helping them. AND, because of this, the cops are pretty dumb! This is the trademark of all these films.
In this case, William is very ably assisted by Eric Blore (who is hilarious as his butler in this third Lone Wolf film). Unlike the last of the Warren William Lone Wolf films (The Lone Wolf Strikes), this one has a very good plot and actually has some entertaining twists and turns. Plus, like the first of the series (The Lone Wolf Spy Hunt), the supporting actors in general are excellent. A very good example of the series.