When Al turns on his radio, the sound heard is the part of the introduction by the Army officer at the beginning of the film played backwards.
Although the wearing of "zoot suits" by Mexican youths in Los Angeles in the 1930's and 1940's are now regarded as the beginnings of a movement toward Hispanic pride in the face of Anglo discrimination, this film hints that Nazi provocateurs were behind it all.
The clip at the beginning of the movie is of Peter Lorre and from "Background to Danger" (1943).