Erros de gravação

A character says that the victim was stabbed through the heart, but the corpse shown at the film's beginning has a knife in its side, several inches from the heart.

When Ruth is talking to her sister Terry, who is in bed, the mirror shows a reflection of her sister with a picture above her bed. But a straight shot before and after would reveal that there is just a wallpapered wall behind her. Later in the movie, a picture is visible above Terry's bed and Ruth's bed, this time correctly matching the mirror.

The daytime overhead general shot of the police car arriving at the Medical Building with the witnesses gives the pedestrians opposite shadows to those of the vehicles. In the following mid shots the direction of light has changed again.

Even identical twins do not have identical fingerprints.

When Terry is comforting Ruth who is crying in bed, the covers are not moving, despite Ruth shaking terribly with sobs "underneath" them. (The split screen is obvious.)

When Ruth is sitting at the dressing table and Terry is standing behind her with her front image reflection shown in the mirror, the mirror image and "Terry"'s movements do not always match.

When Dr. Elliott is sitting on the leather couch in his apartment talking to Lt. Stevenson, a moving shadow (from something above like a boom mic) appears on the lamp behind the doctor.