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.