Der Tod hat ein Gesicht (1961)

Three chemists unveil “Substance L,” a pesticide capable of eradicating all life without harming material assets. When Dr. Zichy, haunted by his work on Zyklon B, dies in a car crash and the lethal vial vanishes, colleague Dr. Cramm uncovers a child’s poisoning. To suppress the scandal, the corporation and justice system commit him to an asylum, until his assistant Barbara risks everything to expose the truth.