A lawyer for two brothers SLOTXO who founded a South African Bitcoin investment firm has told the BBC they categorically deny any involvement in a "heist".
Africrypt, founded by Raees and Ameer Cajee, "absconded" with Bitcoin then valued at about £2.6bn ($3.6bn), according to a complaint to police.
A law firm - Hanekom Attorneys - made the complaint in April on behalf of a group of investors.
But there is uncertainty over exactly how much crypto-currency is missing.
On its now inactive website, Africrypt described itself as "an investment firm exclusively focused on crypto-currency and blockchain technology".
The company, founded in 2019, told investors in only a few years it had grown from a one-man operation running out of a bedroom to "one of Africa's largest and most successful AI trading companies".
Hack claimed
On 13 April, chief operating officer Ameer Cajee wrote to Africrypt clients announcing the firm had halted operations because of a hack.
"Our system, client accounts, client wallets and nodes were all compromised," he wrote.
The letter advised investors not to pursue the "legal route" as that would "only delay the recovery process".
Some of the investors who lost access to their money are represented by law firm Hanekom Attorneys.
Brothers' response
Lawyer John Oosthuizen, who represents Raees and Ameer Cajee, told the BBC the brothers "categorically denied" they had been involved in a "heist" or had absconded with funds.
"There is no foundation to the accusation and there's no merit to those accusations," he said.
"They maintain that it was a hack, and they were fleeced of these assets," he added.