| Director | Kurt Neumann |
|---|---|
| Budget | $495,000 |
| Box office | $3 million |
In Montreal, scientist André Delambre is found dead with his head and arm crushed in a hydraulic press. His wife Hélène confesses to the crime but refuses to provide a motive, and begins acting strangely. In particular, she is obsessed with flies, including a supposedly white-headed fly. André's brother, François, lies and says he caught the white-headed fly.