Two South African brothers have vanished with $3.6 billion of bitcoin in what could be the biggest crypto heist in history

• Ameer Cajee and his younger brother, Raees Cajee, founded Africrypt in 2019.
• Not long after, the siblings, along with bitcoin worth $4 billion at the peak in April, are nowhere to be found.
• Authorities and lawyers are still trying to get to the bottom of the disappearance.

Two South African brothers recently vanished with $3.6 billion worth of bitcoin in what could potentially be the biggest cryptocurrency heist in history.

Local media, including Independent Online and ITWeb, were the first to report on the case.

In 2019, Ameer Cajee and his younger brother, Raees Cajee, founded crypto investment app Africrypt.

Not long after, the siblings, along with 69,000 bitcoins worth roughly $4 billion at their April peak, are nowhere to be found.

It all began in April when Ameer, who is the company's chief operating officer, informed their clients that Africrypt was hacked, compromising their accounts, wallets, and nodes.

In an unusual step, 20-year-old Ameer told them not to report the incident to authorities as this would impede attempts to recover the funds.

A few suspicious customers, however, did report the hack. They contacted Hanekom Attorneys, according to Independent Online, who then tried to track the brothers down. When unsuccessful, Hawks, a police unit in South Africa that targets crime and corruption, was looped in.

"We were immediately suspicious as the announcement implored investors not to take legal action," Hanekom Attorneys told Bloomberg over email. "Africrypt employees lost access to the back-end platforms seven days before the alleged hack."

The lawyers also told cryptocurrency exchanges around the world to sound an alarm if they noticed any suspicious conversion of coins.

FNB, which banked Africrypt, has also been questioned about the episode, according to documents seen by Independent Online. The local bank denied any involvement.

"FNB once again confirms that it does not have a banking relationship with Africrypt. Due to client confidentiality, FNB cannot provide any information on specific bank accounts," Nadiah Maharaj, FNB risk spokesperson, told Independent Online.

As the brothers remain missing, some efforts to get to the bottom of things have hit roadblocks.

For instance, South Africa's Finance Sector Conduct Authority, the country's financial institutions regulator, said cryptocurrency-related matters do not fall under its jurisdiction, Independent Online reported.

Crimes involving crypto are a growing cause of concern for regulators and companies.

Most recently, the Bank for International Settlement criticized the digital asset for its role in illegal activities.

"By now, it is clear that cryptocurrencies are speculative assets rather than money, and in many cases are used to facilitate money laundering, ransomware attacks, and other financial crimes" BIS said.

US Treasury Secretary Janet Yellen, meanwhile, has also been a vocal critic of cryptocurrencies.

"To the extent it is used, I fear it's often for illicit finance," she said in February. "I do worry about potential losses that investors can suffer."