How Dark Web Crimes are Investigated
Because of the anonymous nature of the Dark Web, investigators have their work cut out for them. One of the main ways to catch criminals is by going undercover online, which can sometimes lead to real-life connections when, for example, an officer posing as a seller obtains the buyer's mailing address. Also, the target of an investigation may slip up and reveal personally identifying information. In fact, an investigator with the Internal Revenue Service found an incriminating comment by Silk Road's Ulbricht along with his email address, which would lead to his eventual arrest.
Since many of the transactions conducted via the Dark Web are completed by the U.S. Postal Service, police sometimes are able to match online clues with surveillance footage, handwriting analysis, and other clues. They may even find fingerprints on the package, potentially revealing the sender's identity. Following the money also can be effective, even though the anonymous nature of Bitcoin makes that much more difficult. Still, the Department of Homeland Security has a dedicated task force focused on tracking money laundering via cryptocurrencies.
Other approaches involve the use of sophisticated technology and hacking techniques. For example, the FBI used malware to go after child pornography site Playpen. The software caused users who clicked on the forum to reveal their real IP addresses, which were then sent to investigators. Another hacking technique exploited a vulnerability in the Tor browser, allowing investigators to see the IP addresses of Dark Web marketplaces and users. Ultimately, it's a game of cat-and-mouse.