The Islamic State of Iraq and Syria (ISIS) has been called the world’s richest terror group. While the group generates the majority of its funds through oil fields seized in northern Iraq and Syria, it still relies on a number of other ways to secure financing. Donations from wealthy sympathizers greatly helped ISIS when it was first established. However, now that global governments are aware of ISIS and actively look to track and block all funding efforts through banking channels, donations have become harder to receive. These difficulties have not stopped ISIS from seeking ways to bypass sanctions and money-laundering filters, however. The group has begun to use cryptocurrencies such as Bitcoins as it looks for anonymous and untraceable ways to transfer money.
https://securityintelligence.com/isis-are-they-using-bitcoins-to-fund-criminal-activities/Bitcoin and Silk Road
Many of you know what Silk Road was all about. If you don’t here’s a brief description. Silk Road was essentially an Ebay for criminals. It was an online marketplace mainly for dealing drugs but on top of that you could also purchase guns, hire a hitman and anything else you might need for your supervillain plans. Silk Road used Bitcoin as a payment system. Mainly because of Bitcoin’s anonymity but as you know, Bitcoin isn’t really anonymous, quite the opposite in fact. Hence the guys who didn’t spend enough effort into hiding their trails got caught. Silk Road was closed down in October 2013 by the FBI and its founder Ross William Ulbricht is serving life in prison without parole. Ironically an US undercover agent working on the Silk Road case also stole $700 000 worth of Bitcoin during the investigation. The agent, Carl Force is facing 20 years in prison for various charges.
https://blog.hitbtc.com/is-bitcoin-used-for-illegal-activities/Bitcoin, the Internet currency beloved by computer scientists, libertarians, and criminals, is no longer invulnerable. As recently as 3 years ago, it seemed that anyone could buy or sell anything with Bitcoin and never be tracked, let alone busted if they broke the law. “It’s totally anonymous,” was how one commenter put it in Bitcoin's forums in June 2013. “The FBI does not have a prayer of a chance of finding out who is who.”
The Federal Bureau of Investigation (FBI) and other law enforcement begged to differ. Ross Ulbricht, the 31-year-old American who created Silk Road, a Bitcoin market facilitating the sale of $1 billion in illegal drugs, was sentenced to life in prison in February 2015. In March, the assets of 28-year-old Czech national Tomáš Jiříkovský were seized; he’s suspected of laundering $40 million in stolen Bitcoins. Two more fell in September 2015: 33-year-old American Trendon Shavers pleaded guilty to running a $150 million Ponzi scheme—the first Bitcoin securities fraud case—and 30-year-old Frenchman Mark Karpelès was arrested and charged with fraud and embezzlement of $390 million from the now shuttered Bitcoin currency exchange Mt. Gox.
http://www.sciencemag.org/news/2016/03/why-criminals-cant-hide-behind-bitcoin They have many cases of crimes involving bitcoins.
Just as there are many cases of crimes involving money ( Dollar, EURO, Pound )