Do we believe that assistant to a nations ambassador abroad, could come home and just wander around the office of the head of state and that there would be papers lying openly stating do something ?.
Security would notice anything suspicious or question why someone who hasn't a right to be there could just go wandering about.
It requires a view that somehow the security services guarding the Head of State are letting people wander around offices.
It appears there is a lot more added to somehow make person credible where proof isn't required.