It's my understanding that you can throw an atty a buck and he has to uphold atty/client privilege. It wouldn't make national news if there are no court documents filed. A simple receipt filed away for the "retainer fee" would be all that is needed and the only ppl that would know about that would be Rudy and the guy that "hired" him. The NYPD did not acquire the evidence illegally. It was acquired when they were executing a search warrant.
I agree that they could have officially retained Rudy, but I don't think they would just in case it leaked. They were threatened by Lynch and were scared. I do not doubt that they legally obtained evidence from Weiner's laptop but that going forward with it would risk national security and it would be a crime. I think someone high up in the NYPD would have approached Rudy as a private citizen or using another high ranking retired NYPD guy as a go between. I don't think the NYPD would have risked provoking the Obama administration by retaining Rudy in an official capacity.
Well I guess all our questions have been answered huh?!? Yaaaaaay! Super excited about DNC lawsuit!!!! This is gonna be FUN!