https://arstechnica.com/tech-policy/2018/05/the-doj-is-reportedly-probing-the-murky-world-of-bitcoin-trading/

Bitcoin and other cryptocurrencies have taken a wild ride over the past 18 months. Now, according to Bloomberg News, the US Department of Justice has opened a criminal investigation into whether price manipulations have contributed to the meteoric rises and crushing falls.

The coins prosecutors are examining include bitcoin and ether, which have both bounced up and down over the past 18 months. In 2017, after bitcoin began the year with a price of about $1,000, it soared to just below $20,000 in December and then finished out the year at about $13,900. Ether followed an even steeper trajectory, beginning 2017 at about $8 and finishing at about $747. Prices for both currencies have experienced major volatility over the past six months.