The Union Films catalog, Films for ’48, described The Investigators.

One reel satire, musical, on the Un-American Activities Committee.
Three weird demons investigate the common man, produce their idea of
“the perfect citizen” (a robot) and laud their idiot sleuth--all in song. 

The Investigators (1948) 16mm, sound, b&w, 11 min.

Produced by Union Films

Director: Max Glandbard

Script: Lewis Allan [Abel Meeropol]

Camera: Victor Komow

Sound: Richard Patton

Music: Serge Hovey

Cast: the John Lenthier Group (including Herschel Bernardi)

As a stage production, The Investigators was presented by the Civil Rights Congress, which had been founded in 1946 and took on a broad range of court cases. Indeed, one of its earliest cases was that of Carl Marzani, head of Union Films (indicted for concealing his past CPUSA membership while serving in the Office of Strategic Services during WWII). Also involved with production was the Chicago Arts Committee for Wallace, Theater Section, supporting Progressive Party presidential candidate, Henry Wallace in the 1948 election.

REFERENCE:

Charles Musser, “Carl Marzani & Union Films: Making Left-wing Documentaries during the Cold War, 1946-1953,” The Moving Image 9.1 (2009): 116-72.