He actually scammed a well known steemit user and reputed steem based banking initiative.

Perhaps you heard about "Bank of Neoxian" on steemit. It is a well know banking project by Neoxian. The Bank provides loans to users with contracts. The user @kibria365 agreed to get loan 45 Steem and repay 51 Steem total. He was actually scamming and changed keys which rightfully belongs to @neoxian. You will find more details from below. Stay safe.

https://steemit.com/dead/@neoxian/steem-inc-responded-they-decided-to-assist-the-scammer-in-robbing-me-by-refusing-to-return-the-account-to-me