There's been a sensational twist in the case of the cryptocurrency CEO who died, taking $263 million with him to the grave.

Boss of Quadriga CX Gerry Cotten reportedly died suddenly in India last December -- and was the only one with the password to millions in Bitcoin, Litecoin and Ether stored by the company.

But after breaking into his laptop in an attempt to recover the funds, court-appointed auditor Ernst & Young found the ‘cold wallets’ were in fact empty.

“In April 2018, the remaining bitcoin in the Identified Bitcoin Cold Wallets was transferred out bringing the balances down to nil,” said Ernst & Young in its report.

The auditors found a total of six cold wallet addresses used by Quadriga, five of which had been empty since April 2018 and the other used to transfer coins into the far smaller online ‘hot wallet’.

The sixth wallet is also now empty, the last transaction having occurred on 3 December 2018, just days before Cotten’s death.

In the four years prior to April 2018 the balances in the wallets ranged from zero to 2,776 bitcoin.

Three other cold wallets believed to have been used by Quadriga were also found, two of which were empty.

So what happened?

As well as uncovering the missing cryptocurrency, Ernst & Young found a number of other suspicious behaviours in its investigation of Quadriga.

“The company had limited books and records, no financial records or reporting appears to have been undertaken,” says Ernst & Young.

The company had also been embroiled in legal troubles prior to Cotten’s death, with the Canadian Imperial Bank of Commerce at one point freezing its funds as it was unable to determine the identity of certain funds’ owners.

Independent journalist Amy Castor has been closely following the case and has also found some red flags.

“Jennifer Robertson is Cotten’s widow, a woman he bequeathed all of his worldly belongings to shortly before his death. In addition to becoming the largest shareholder of Quadriga, she now owns a yacht [which was purchased by Cotten in 2017], an airplane, and millions of dollars worth of property,” reported Castor.

Castor methodically maps out a timeline of the events leading up to Cotten’s death.

One particularly noteworthy event is Cotten signing his will, which leaves all his belongings to Robertson, on November 27.

While a misspelled death certificate (‘Cottan’ rather than ‘Cotten’) has aroused suspicion over a possible fake death, the hospital in India where he passed has since confirmed the death.

Around 363,000 registered users are still owed a combined total of $267 million in cash and cryptocurrency.

The next hearing is scheduled for 18 April.