Tor Browser, since its inception, had been a target of law enforcement. There are many valid uses to the browser which provides anonymity to its users. People who live in oppressive regimes, for example, can access the Internet via this anonymous browser.
Also, journalists, whistleblowers, and law enforcement are also heavy users of Tor. The Tor network keeps its anonymity by routing traffic through many nodes located around the world. This makes it difficult to pinpoint where a particular user is located, Washington Times reported.
That being said, Tor is also a hotbed of criminal activity like drug dealing and child pornography. It is for this reason that many organizations have tried to bring down Tor. Vice's Motherboard, on Wednesday, reported that a "university-based research institute that operated its own computers on the anonymous network" was the one responsible for the crackdown on the Silk Road 2.0, an anonymous marketplace for drugs.
Carnegie Mellon has not confirmed this but there is evidence of their possible involvement. For one, CERT/Carnegie Mellon researcher Alexander Volynkin was supposed to deliver a talk entitled "You Don't Have to be the NSA to Break Tor: Deanonymizing Users on a Budget" at the Black Hat Conference in Las Vegas last August.
Part of the synopsis of the talk said, "A persistent adversary ... can de-anonymize hundreds of thousands of Tor clients and thousands of hidden services within a couple of months [for] just under $3,000."
Tor has released a strongly worded response to this report. They said, "Apparently these researchers were paid by the FBI to attack hidden services users in a broad sweep, and then sift through their data to find people whom they could accuse of crimes." Tor has also included an allegation that the researchers received $1 million for their efforts.
Tor also added, "We teach law enforcement agents that they can use Tor to do their investigations ethically, and we support such use of Tor - but the mere veneer of a law enforcement investigation cannot justify wholesale invasion of people's privacy, and certainly cannot give it the color of 'legitimate research."