This is the relevant reference from the Books where Proof is mentioned.
It is not meant to be anything other than the facts of the matter.
Arrive at your own conclusions.
I wish you well,
I shall accompany you to the cart and see that you board safely." I had no intention of letting him out of my sight. Although I had no proof of the sort which might convince a praetor I was confident that it was Ephialtes of Torcadino who had stolen the letters. It was ironic. I had ridden in the very cart with him.
Mercenaries of Gor Book 21 Page 244