The US Department of Justice now wants to extradite him to face 21 counts of money laundering and other financial crimes in the US.
Mr Zakharov said: “They were on the beach and his wife was swimming, and when she turned back she saw a lot of people with sunglasses near her husband, and that’s how he was arrested.”
Russia has also filed an extradition request for Mr Vinnik on lesser, unrelated charges.
The Greek government is now in the process of deciding between the two requests.
Via his lawyer, Mr Vinnick told the BBC he denies having any connection to Always Efficient.
He added: “BTC-e is just a web platform for buying and selling Bitcoin – not an exchange. As such it cannot be held responsible for the source of money used to buy Bitcoin, no more than a bureau du change can be held responsible for exchanging a stolen $100 note into pounds sterling.”
A National Crime Agency (NCA) spokesman said it didn’t “routinely confirm or deny investigations” but recognised “the very real risks to the UK and the UK’s financial sector from large-scale, complex money laundering.”
He added: “Tackling money laundering is a high priority for the NCA, and we have a number of national and international operations running against the criminals involved, working in close partnership with partners in law enforcement and financial regulation.”
Mark Karpeles was arrested and charged with embezzlement related to payments worth £1.7m. He says these were legitimate loans signed off by an accountant.
He’s also charged with manipulation of data. He denies all the charges – none of which relates to the loss of the 650,000 bitcoins.
He told the BBC he was doing all he could to return funds to customers and added: “I am very sorry that when I was in charge things happened the way they did.”