Factual error: Ed Crane is executed by electrocution at the end of the film. However, in 1949, when the film is set, the gas chamber was used as the sole method of execution. According to the California Department of Corrections and Rehabilitation, California has never used the electric chair as a means of capital punishment.
Factual error: In one scene, after finishing playing the middle movement of the Sonata Pathetique, Bertie states that Beethoven was completely deaf when he wrote it and never heard the notes. This is untrue as the sonata was written in 1797/8 and Beethoven did not go totally deaf until 1823.