VIC Deliberate False Evidence to Undermine Trust?

What is the term for deliberately false evidence to undermine trust? I will explain better:
Someone unknown unexpectedly for you comes up with a "helpful" "evidence" and tries to help you. But this "help" is a false evidence deliberately form the beginning and organised such a way so opposition can easily find it and explain that it was a false evidence. And it starts working against you. But you never asked for such "help" - it was pre orchestrated by the opposition deliberately to put you in a bad situation. By itself it is a forgery, but in indirect way.

 

Say, it is more a theoretical question. I thought there is a special terminology for such cases as there are a few around. Thank you very much for the response.