beyond a shadow of a doubt

So I thought if it's beyond a shadow of a doubt, he would not get convicted.

English astronomer Arthur Eddington’s eclipse expedition of 1919 proved Einstein’s theory of general relativity beyond a shadow of a doubt.

“You could tell beyond a shadow of a doubt that I was uncomfortable,” he said.

“We proved their innocence beyond a shadow of a doubt,” Della Donna said.

Then he tells her: "Your sister wasn't there. I can prove beyond a shadow of a doubt that your sister wasn't there."