American law enforcement just illustrated how important cryptocurrency has become in the criminal world. Federal agents have charged Ohio resident Larry Harmon for allegedly running a darknet-based Bitcoin "mixer" that laundered the equivalent of roughly $300 million for drug dealers and other crooks. Helix, as it was called while it ran between 2014 and 2017, reportedly let customers pay to send Bitcoin in a way that hid the true source. It operated with "brazenness," the IRS' Don Fort said. Helix supposedly partnered with AlphaBay to serve the darknet black market's customers, and advertised Helix on the Grams search engine (which Harmon apparently ran) as a way to hide deals from police.