Opposing forces are at work in a dual plot that makes "Docks of New Orleans" an interesting Charlie Chan mystery. An international gang attempts to steal a secret gas formula that they can no longer prevent from being shipped to rival forces in South America. At the same time, the inventor of the gas formula seeks revenge on the owner and partners of the LaFontanne Chemical Company who paid him a measly sum for the formula, while cutting him out of huge profits and a partnership for himself.
As usual, Charlie Chan casts a wary eye in all directions and pursues his investigation with excruciating patience. Roland Winters portrays Chan for the second time in this Monogram release. As before in "The Chinese Ring", Victor Sen Yung appears with a confused identity - early in the film, Pop Chan refers to him as Number #2 son, and somewhat later calls him by the name of Jimmy. Near the end of the movie, Chan calls out to Tommy. For those not as familiar with the Chan characters, Tommy as Number #3 Son was portrayed in earlier Monogram's by Benson Fong. Was this a confusing lapse in continuity, or was Monogram by this time goofing on it's audience?
Mantan Moreland is back again as Chan servant Birmingham Brown. In an interesting twist, son Jimmy/Tommy retrieves a hijacked vehicle from a parking garage with Moreland's character along for the ride as a passenger; Birmingham is the Chan chauffeur in earlier films. Birmingham also reprises a humorous exchange with an uncredited Haywood Jones as "Mobile" Jones, reminiscent of his "Pidgin' English" dialog with Ben Carter in "The Scarlet Clue" and "Dark Alibi".
The key to solving the mystery is provided by Tommy and Birmingham in concert (no pun intended) when they offer a rendition of "Chop Suey Boogie" with Birmingham on piano and Tommy on violin. The high pitched screech of Tommy's violin causes a radio tube to break, leading Charlie to theorize that the deadly gas formula is released in the same manner. To eliminate the three partners who bilked him out of a fortune, inventor Swenstrom cleverly uses his wife's radio broadcasts to break tubes planted in the victims' home and office radios, set to the precise station at the appropriate times.
Granted, "Docks of New Orleans" is not high drama, and there are slow moments. Captain McNalley (John Gallaudet) of the New Orleans Police Department is particularly inept in dismissing clues and evidence that Chan immediately considers important. All considered though, this is an entertaining mystery and a nifty entry in the Chan series.