"There has been no reason to release him," Remus said mildly. "Yes, the veritaserum revealed that he believes he is no danger to us, but without a Legilimens to delve into his mind, we cannot be sure what the Dark Lord may have done to him. He could be a sleeper agent, perhaps. Harry thinks, and I agree, that it is best to keep Draco Malfoy confined for the present."