https://www.reuters.com/article/us-crypto-currency-safrica/south-africa-crypto-exchange-brothers-disappear-after-client-cash-vanishes-lawyers-say-idUSKCN2E11XE >Lawyers for investors in a cryptocurrency exchange in South Africa, which told clients in April their accounts had been hacked, say $3.6 billion has disappeared from the platform and that the two brothers who ran it cannot be traced.