Mt Gox protest
Kolin Burges travelled from London to Tokyo to confront Mt Gox owner Mark Karpeles over £85,000 worth of bitcoins.YouTube: Jon Southurst

A group of internet security experts have launched an independent investigation into the collapse of bitcoin exchange Mt Gox, which at one point hosted 80% of trades in the popular digital currency.

The Financial Times reported that a group of experts led by Jason Maurice of security consultancy Wiz Technologies is pursuing an independent probe into what happened at the exchange. The group were optimistic that the culprit or culprits can be traced.

Mt Gox might have become victim to a series of raids beginning in 2013, in which a hacker gained access to the exchange's database of account holders, Maurice told the newspaper. Subsequently, the hacker "assigned himself new accounts with faked cash balances, and bought and withdrew the virtual currency at will."

Maurice added that the control systems under Mt Gox chief Mark Karpelès were so basic that the thefts went undetected.

"There were no processes to realise that coins were leaking," said Maurice.

"It looked like normal customers withdrawing money; Mark didn't know that thousands of coins were being stolen every day."

However, Maurice believes that Karpelès, who is also a suspect in the crime, has no direct link to the theft, saying the 29-year-old Frenchman lacks the "social intelligence" necessary to pull off a sustained deception.

Maurice told FT that he has a list of "potential suspects" – based on certain leaked data and deeper analysis of other Mt Gox trading-log data available on third-party sites.

He noted that he still needs full access to the Mt Gox database of customer addresses in order to identify suspicious trades with reference to the blockchain, the central ledger that logs all transfers between bitcoin addresses.

"If we can reconcile everything, we can figure out where the money went," he said.

In July, Tokyo police said they had launched a formal fraud investigation into the disappearance of as many as 650,000 bitcoins from the Shibuya-based exchange.

Mt Gox collapsed after reporting that 850,000 bitcoins were stolen in what it claims was the result of a two-year-long cyber attack. The company later said it recovered about 200,000 of the missing bitcoins.

The company filed for bankruptcy protection in Japan on 28 February and subsequently in the US.

The exchange later filed for liquidating its assets following its failure to restructure its business under the country's bankruptcy protection scheme.

Subsequently, a Tokyo court ordered the administrator of the bitcoin exchange to start liquidating the company's assets to pay back its creditors.

On 18 June, a Texas bankruptcy court approved Mt Gox's application for bankruptcy protection of its US assets.