For years, buyers and sellers of illicit goods on the dark web have often turned to Reddit to discuss the latest developments in the internet's underground. It's only natural, then, that internet cops would follow the criminals.

On Tuesday, a hacker that goes by the name InsanityDRM posted on the subreddit dedicated to the Tor hidden service marketplace Trade Route to announce that he had obtained the personal information of a rival hacker named PhishKingz, a practice known as doxing. Shortly after that, an Internal Revenue Service (IRS) cybercrime agent contacted him in private inquiring about the dox, according to a screenshot obtained by Motherboard.

Earlier this year, Motherboard revealed that the IRS paid a cybersecurity firm to scour the dark web. Now, it seems IRS's own agents are doing the scouring. In this case, he identified himself on Reddit as an IRS special agent. The Reddit username associated with the agent does not have any public posts on Reddit but uses the website's messaging system.

Reached via email, the agent, who has investigated crimes on the dark web and involving cryptocurrency, declined to comment, and requested that Motherboard not reveal his identity. Motherboard independently confirmed that the Reddit account and email address in the screenshot belong to the agent. An IRS spokesperson did not immediately respond to a request for comment.

The IRS has been investigating dark web crimes for a while. Earlier this year the agency investigated the case of a man that was arrested and sentenced for advertising money laundering services on an Onion site, as well as the case of a man who conspired to sell heroin on the marketplace AlphaBay, which shut down last summer.

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