It doesn't make sense that it would be related to the coins seized by the FBI because they wouldn't have any reason to split them into different wallets like that. It is alleged that they are related to the Silk Road controlled wallet/MtGox wallet because at one point they were closely related (according to one Reddit user).
What is known however is that whoever has the keys is an early adopter who had moved over 37,000 of those BTC into the wallet June 2011... Either they were some sort of vendor at Silk Road or they were a mega whale trader who had plenty of cash to burn in 2011.
The current holder of the coins sure isn't saying anything to identify themselves ahead of time either which is a little sketchy. If it was related to the MtGox repayments or "lost coins" they would have told their lawyers about it beforehand. By dumping coins onto the market they could be looking to reposition themselves lower since they could cause panic selling and trigger stop loss orders like a domino effect.