Here you go:

"An Ohio man was arrested for his operation of Helix, a Darknet-based cryptocurrency laundering service.

In the three-count indictment unsealed Feb. 11 in the District of Columbia, Larry Harmon, 36, of Akron, Ohio, was charged with money laundering conspiracy, operating an unlicensed money transmitting business and conducting money transmission without a D.C. license.

According to the indictment, Harmon operated Helix from 2014 to 2017. Helix functioned as a bitcoin “mixer” or “tumbler,” allowing customers, for a fee, to send bitcoin to designated recipients in a manner that was designed to conceal the source or owner of the bitcoin. Helix was linked to and associated with “Grams,” a Darknet search engine also run by Harmon. Harmon advertised Helix to customers on the Darknet as a way to conceal transactions from law enforcement."

https://www.justice.gov/opa/pr/ohio-resident-charged-operati...

Right. For some reason I misread your previous comment as miners, not mixers. But now I don't fully understand why you brought mixers up, mining is a different activity.

I dunno, from the list of charges, you can see that there is no law against mixing per se.

It could just as well have been a prosecution of hawala or something.

The laws seem to be pretty general.