This account is supposed to be an internal worker of Steemit but he send that quarter million of Steem to Poloniex and Bittrex to an individual wallet, not a Steemit official one
Steemit send him an extra 49k of Steem, he changed the key and the money was later transfered out of Steemit
This is just the top of the iceberg, we have tons of information that we will we posting eventually. Hope you guys can support us to make a more clean and transparent community.