Trivia

Amalia's daughter is portrayed by a young actress using the professional name Gogó. She is actually the daughter of director Román Viñoly Barreto. In her acting career, she appears in only a few films, all directed by her father. She would go on to receive a Doctorate in Medicine and then a Doctorate in Psychiatry.

Per Turner Classic Movie's Eddie Muller on Noir Alley, the October 29, 2022 broadcast was the premiere of this movie on TCM. This 1953 film from Argentina had undergone a complete digital restoration in the United States by The UCLA Film and Television Archives, funded by U.S. sources and produced by the Film Noir Foundation. It is believed not to have been commercially shown previously in the United States.

Edvard Grieg's In the Hall of the Mountain King, a dark, ominous sounding composition, is heard several times in the score. It is whistled by The Professor as well as background incidental music. This the same tune whistled by Peter Lorre's character in M el Maldito (1931).

Buenos Aires, often called the Paris of South America, appears to have a similar sewer system as its storied French counterpart. Per the film director's eldest son, Daniel, who was 10 during filming, the climax was filmed in the city sewers using extras who actually were homeless people living beneath the city.

Mariano Vidal Molina's character is named Lange, after Fritz Lang, the German director of M el Maldito (1931), on which this film is based.