Things aren't going so well for Australians who've invested in cryptocurrencies. 
The digital currency world, buoyant for so long, went into meltdown this month, with prices collapsing to near historic lows, and over a quarter of the global market evaporating. 
It's the crash of an unregulated market full of inherent risks, but it's also a market increasingly being used by criminal gangs around the world. 
Today, ABC Four Corners reporter Stephen Long on cryptocurrency's dark side. 
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Stephen Long, reporter, ABC Four Corners