威爾斯啟發了黑色電影風格，又以這個類型風格來處理本片。平靜小城受人尊敬的教授原來是納粹餘孽，聯邦密探微服偵查，引發出連場殺戮。威爾斯飾演教授，與康城影帝愛德華．羅便臣飾演的聯邦密探，大鬥演技，成為一時佳話。殺人毒計更為影片帶來奧斯卡最佳原著劇本和威尼斯影展最佳電影金獅獎提名，又是他最賣座的電影。Welles, who had been an original inspiration of film noir, skillfully incorporated the noir element into this thriller of deceit and murder. Welles plays a well-respected small town professor who was actually a Nazi fugitive. The investigation by the FBI agent played by Edward G. Robinson's has brought about murderous consequences. The film was nominated for an Oscar in Best Original Screenplay and a Golden Lion at Venice Film Festival; it was also Welles' biggest box-office success.