Bitcoin uses blockchain technology. How did the $87 million theft happen ??
It says in the article that the hackers has able to steal thru cyber-intrusion. So they gained un authorised access to the victims pc and perhaps got their private key and passwords.
A task force was set up and a preliminary investigation revealed that hackers had used remote hijacking techniques to gain access and control of cryptocurrency accounts belonging to the victim only identified as Zhang with nearly no footprints of the crime.
https://www.ccn.com/chinese-police-arrest-hackers-behind-87-million-cryptocurrency-theft/At least the hackers have been caught and we all know how tough Chinese law is. This guy will be rotten in jail if found guilty.