Back in August, when the FBI was investigating Freedom Hosting, an anonymous web hosting company known for sheltering child porn, it managed to clone an entire server of Tor Mail, a popular anonymous webmail service hosted on the company's network.

According to Wired, court documents filed in relation to a credit card fraud case reveal that the FBI is using Tor Mail's data in completely unrelated investigations. The case in question involves Florida-based Sean Roberson, who, along with three other men, allegedly ran a website called fakeplastic.net, which supplied fake credit cards and hologram stickers.

When the FBI came to know that orders for counterfeit cards were sent to a Tor Mail email account, platplus@tormail.net, the investigation agency obtained a search warrant for it in order to search its own copy of Tor Mail data.

The news is a setback for those who bet big on Tor Mail, especially in the wake of Edward Snowden's revelations regarding the US government's PRISM program to monitor Internet users. Meanwhile Tor Mail, which stopped working on August 4, has posted a message on its homepage that reads: “We have no information to give you or to respond to any subpoenas or court orders”.

In another email case, the FBI last year asked for private SSL keys from Lavabit, a secure email service used by Snowden. According to the investigation agency, they were interested in only one of Lavabit's 400,000 users. But the company didn't comply with the orders. They shut down and appealed the ruling instead.