Sleeper agents, magical time-bombs set to hunt down Death Eaters and have no formal training to reduce civilian casualties. No wonder Kingsley wasn't willing to make just anyone an Auror... you'd have to trust them to not abuse the power. Harry remembered what Hermione had said. Draco would more than likely be a target, but so could Narcissa. What's the difference between a Death Eater, a scared boy forced to take the mark, and his mother to an Auror?