A gang of 5 robber forced a Businessman to reveal his private keys containing 450 Bitcoins.

The gang acted as if they were police and followed the businessman to the his car. After keeping him in there for like 8 hours the businessman finally gave up and gave his private keys.

Afterwards police launched an operation and caught the robbers. Some amount of these Bitcoin's are told to be spend but the exact numbers are still missing.

https://kriptokoin.in/istanbulda-bitcoin-gaspi/

I was thinking about that lately and this accident happened. What else can be done to protect these Bitcoins. I mean a Bitcoin millionnaire should be more careful to protect his private keys.

Is there any useful system providing that? Maybe in the future there will be Bitcoin banks to save these Bitcoin and reaching to them will require more than 1 password or key...

Do you have any ideas?