Gary Cooper's cancer was at such an advanced stage that frequent breaks were required during filming for him to receive oxygen so he would be able to proceed to the next scene.
Just after filming ended Gary Cooper's cancer was found to be terminal on 27 December 1960. Cooper himself was not even informed that he had cancer until the following February.
Released one month after Gary Cooper's death, the film received poor reviews and was a financial failure.
After "The End" is flashed on the screen and fades out, a disembodied voice is heard under the black screen asking the audience not to reveal the identity of the killer.