Around $51 million worth of bitcoin were moved by the hackers that breached the security of cryptocurrency trading platform Bitfinex in 2016, and stole nearly 120,000 BTC at the time.

According to the International Business Times, the transactions have been closely tracked by blockchain large transaction monitor Whale Alert and blockchain sleuths, who found 620 BTC worth $7 million were moved on August 2 over four transactions, with one of the transactions moving 308.4 BTC alone.

On July 30, the hackers moved 448 BTC worth nearly $5 million, and on July 29 moved another $5.3 million in a series of transaction. The day before that, a massive 2,550 BTC, worth well over $27 million, were moved.

In total, over $51 million worth of bitcoin were moved in the last 10 days. While every movement has been tracked on the blockchain the figure represents a small amount of the total that was stolen from Bitfinex. At the time, the 119,756 BTC Bitfinex lost were worth around $72 million, but because of bitcoin’s price rise over the last few years, they’re now worth $1.3 billion.

The hackers are likely moved the funds between wallet addresses in a bid to figure out how they can launder the funds and withdraw them, a task that has been made harder by strict anti-money laundering (AML) and know-your-customer (KYC) checks enforced by prominent cryptocurrency trading platforms.

It’s also possible the hacker is trying to negotiate with Bitfinex. On the whitepaper of its LEO token, the exchange appeared to give them a chance to return the funds while keeping a percentage as a “reward for collaborating in finally resolving this issue.”

It’s worth noting that in June 2019, authorities in Israel reportedly arrested two brothers involved in cryptocurrency phishing schemes and the Bitfinex hack.

Featured image by Aleksi Räisä on Unsplash