According to The Verge, a hacker associated with the hacking group Anonymous recently infiltrated one-fifth of the Tor based websites on Freedom Hosting II; the largest host site on the Dark Web. Tor is a software which helps encrypt websites to make them anonymous. The Dark Web is a part of the World Wide Web, but only accessible through special software and authorization codes. It allows people to hide their identity and it is a common place for criminals to purchase and deal materials.

The hacker shut down more than 10,000 websites, but not all were regularly used. According to the report, some of the websites contained child pornography and the majority of the others were political blogs. Whenever anyone attempted to access a hacked website, a message appeared that read: “Hello, Freedom Hosting II, you have been hacked.” The message also contained a list of what the hacker discovered and an email address to contact them.

Freedom Hosting, the original, was prosecuted in 2013 for child pornography. Initially, the hacker claimed to only want to look through Freedom Hosting II, but the child pornogrpahy websites changed his mind. Each website on Freedom Hosting II is supposed to use 256mb of data, but the websites containing child pornography had gigabytes of data.

“This suggests they paid for hosting and the admin knew of those sites,” said the hacker in an email interview with Motherboard. “That’s when I decided to take it (Freedom Hosting II) down instead.”

According to Tech Times, the hacker accumulated 75 total GB of files and 2.6 GB of data from the host server. 30 GB of the files were from the child pornography websites. The hacker claimed this was his or her first hack and even provided a 21-step process on how the did it.

For a ransom, the hacker charged Freedom Hosting II .1 bitcoin (about $100).

In the interview with Motherboard, the hacker said they will provide details of the hack to a security researcher who can then give it to law enforcement. It will likely be difficult for the FBI to determine any individuals involved in the child pornogrphy websites because they have already been compromised, but there may still be clues.