I think the answer that it would jeopardize their source is a valid answer to that question.
perhaps, but I think the question being avoided is why would anyone outside of the chain of custody involving evidence collected by a government entity have access consistently and repeatedly when no one else does ?
There are several reasons not to trust Coin Fire that are sitting out there on the Internet with about 5 minutes of research. The guy continues to lie in the public about his identity. His HashTalk AMA gave him the opportunity to own up to it being just a pen name or his real identity and he decided to stick with the lie. That's just one. There are several others.