The anonymous emailer also claims it's "about money."

An email purported to be from the hacker or hackers behind the HBO breach is making a fresh wave of threats against the network. While the sender of the email, received by The Hollywood Reporter, appeared to use a pseudonym, the sender offered evidence of hacked materials to buttress the claim.

"HBO (specially Poor Richard) is Bluffing. We have 'STILL' full access to their webmails....," the email said in an apparent reference to CEO Richard Plepler's memo Wednesday to staff that downplayed the likelihood of widespread email exposure.

As the story grew and the investigation widened, Plepler told HBO's 2,500-plus staff: "We do not believe that our e-mail system as a whole has been compromised, but the forensic review is ongoing."

The email, which came from someone calling himself Kind Mr. Smith, promised that proof of his claim of having emails is coming Sunday.

As for the motive, the email said, "It's just about money. We have weeks of negotiations with HBO officials, but they broke their promises and want to play with us...So we have one option....Wait till Sunday. HBO is Falling..........."

If that claim is true, then it raises the prospect that a ransom demand was made to HBO.

It is unclear if the author of the email is involved in the hack, which resulted in the leaks of such HBO shows as Ballers and Room 104. As proof, the email offered what appeared to be a genuine script for the upcoming episode of Game of Thrones as well as a treatment of the same episode. However, those two items have been circulating on the internet for days.

HBO declined to comment.