A group of hackers called “The Dark Overlord” announced last week it hacked into the computer system of a law firm and stole approximately 18,000 documents connected to the September 11th attacks and the subsequent insurance payouts. This gang of cyber thieves demands a ransom paid in Bitcoin, and threatens to release all documents on the internet unless its demands are met. According to one report from the Financial Times, the group also stated it would sell the file cache to a buyer–whether it be a terrorist group or government–for a sum.

“If you’re one of the dozens of solicitor firms who was involved in the litigation, a politician who was involved in the case, a law enforcement agency who was involved in the investigations, a property management firm, an investment bank, a client of a client, a reference of a reference, a global insurer, or whoever else, you’re welcome to contact our e-mail below and make a request to formally have your documents and materials withdrawn from any eventual public release of the materials,” The Dark Overlord wrote in a note posted on Pastebin, according to Motherboard. “However, you’ll be paying us.”

The goal of The Dark Overlord appears to be monetary gain, not necessarily fueling 9/11 conspiracy theories. Motherboard reports the group’s intent is to spark the interest of individuals believing in the numerous (and debunked) conspiracy theories about the attacks in order to drive up the price for documents. The group took to a Twitter account–since deactivated by the social media company–and claimed, “We’ll be providing many answers about 9.11 conspiracies through our 18.000 secret documents leak,” as a blatant attempt to spur enthusiasm within those communities. However, the group disclosed during an interview with Forbes that Bitcoin is what it’s really after.

“We’re doing this to fuel our Bitcoin wallets,” said The Dark Overlord while speaking to Forbes.

This latest extortion scheme isn’t the first cyber attack launched by The Dark Overlord. In April 2017, the hackers leaked new episodes of Netflix’s Orange is the New Back after the video streaming company declined to meet their demands. They also attacked numerous U.S.-based businesses and hospitals.

The stolen documents are believed to be from the law firm’s insurance and business clients, including Hiscox and Lloyd’s of London. Both companies denied a breach of their internal files. The Dark Overlord didn’t name the law firm affected.

“The law firm’s systems are not connected to Hiscox’s IT infrastructure, and Hiscox’s own systems were unaffected by this incident,” said a Hiscox spokesperson while speaking to Forbes. “One of the cases the law firm handled for Hiscox and other insurers related to subrogation litigation arising from the events of 9/11, and we believe that information relating to this was stolen during that breach.”