1.Silk Road
Ross Ulbricht, the pseudonymous proprietor of the website Silk Road, used Bitcoin for illegal transactions in drugs and arms. For two years between 2011 and 2013, Silk Road became a favourite online marketplace - completely anonymous from law enforcement agencies - for drug mafias, and a headache for authorities. People sold drugs worth millions on the website, and all transactions were done using Bitcoin. Drug mafias could easily buy any contraband imaginable at a single platform, just like Amazon or eBay. Within months, the website became the leader of the "darknet", with over 900,000 users and the annual turnover of $1 billion. Ulbricht was arrested in October 2013, and the site was shut down. But soon, it was surpassed by similar "darknet" websites that operated secretively, using domain names like .onion. Ulbricht was convicted for life on drug trafficking, criminal enterprise, aiding and abetting distribution of drugs and money laundering.
2.Rise and fall of Bit Instant
The chief executive officer (CEO) of Bitcoin exchange, BitInstant, Charlie Shrem, a 27-year-old young ambitious entrepreneur was fascinated by the idea of having a currency with no third party control after he heard about it from a friend at the age of 19 in 2011. After he bought a couple of bitcoins - at a dirtcheap price at that time - he started Bitcoin exchange from his home and soon caught the attention of young investors like Winklevoss brothers who pumped in over $1.3 million in his company. It was a meteoric rise, and so was its fall. After he moved to a nice office with over 30 people working for him, the company partnered with giants like Walmart, Walgreens, and Duane Reade where anyone could buy Bitcoins through BitInstant. The business was good and growing with revenue reaching over $1 million in a month, but greed has no limit. Shrem started facilitating transactions on 'darknet' leader Silk Road, and soon he was in the FBI net. After he was arrested in 2016, he pleaded guilty in the court. He claimed he facilitated one customer, BTC King owner Robert M. Faiella, whose customers (or drug mafias) were using Silk Road. They both were accused of the sale of Bitcoins worth $1 million to Silk Road. Shrem was sentenced to two years in jail. This incident sent shockwaves in the Bitcoin world, and people started associating the virtual currency as a means to launder money.