Agreed, and furthermore, it shouldn't matter at all. If the worst Russian Intelligence can do is use real evidence to prove a crime was committed, that's an easily solvable problem both by not committing crimes and by prosecuting crimes committed with transparent, due process.

It really is a very silly argument.

"Your honor, in my defense, the guy who saw me shoot the victim, called the police, and submitted some of the damning evidence to them was a known mafia member, untrustworthy, and had committed crimes against me in the past."

"Okay, and what do you have to say about all of this other corroborated evidence from trustworthy sources?"

"Well they wouldn't have found it if he hadn't pointed it out!"

I don't think he was a Russian spy, but I am also sure that it's irrelevant.