Coincheck targeted by suspicious traffic for weeks before NEM heist

TOKYO -- Suspicious communications between the computers of Tokyo-based cryptocurrency exchange Coincheck and unidentified servers outside Japan began weeks before the Jan. 26 theft of 58 billion yen ($542 million) of the cryptocurrency NEM, a new finding suggests, a person close to the police investigation said.

The finding suggests someone hacked into the Coincheck system via employee email and stole a "private key" necessary to transfer NEM.