I'm not an expert in this, but i think the first-sale doctrine only applies if the phone is in similar condition as the new ones you get from apple (or if it's used, you say that it's used, etc). The seller of the wiretapped phone would probably not be protected.
I do not think it is fraud to print the Apple iPhone X US-version 64GB Black code on a box that does in fact contain an Apple iPhone X US-version 64GB Black
Trademarking your UPC would not work, as someone reselling your product is protected by the first-sale doctrine. If I buy a bottle of Pepsi(tm), I can use Pepsi's trademarks when selling that bottle to someone else.
if you have tons of proof about a murder, it's almost certain to fall under one of the exceptions to the doctrine. e.g, if law enforcement would have discovered the evidence anyway, it is not excluded.
there's plenty of people who think defending a criminal at all is ethically dubious. Depriving criminal defendants of the most effective defense by applying social pressure to their attorneys is not a good road to walk down.