The Plot Thickens (film)

The Plot Thickens is a 1936 mystery film directed by William Sistrom, starring James Gleason and ZaSu Pitts, who plays the schoolteacher and amateur sleuth Hildegarde Withers from Stuart Palmers stories. Gleason reprised his role as Hildegardes friendly nemesis, Inspector Oscar Piper, from RKO Radio Pictures previous Hildegarde Withers films.

Source: Wikipedia