"Don't be ridiculous, Bletchley, of course he knows you're a death eater. The whole auror department probably suspects it. You just keep your nose clean, and things will stay that way." Did he honestly think he wasn't known to them?
But leaning against the table, he made sure Bletchley understood exactly what he wanted. "I need you to tell Vaisey that I have his mother. I'll keep her safe, and out of harm's way in exchange for his co-operation."
"We need him to spy on the aurors, and on his boyfriend, Weasley. I want details on everything going on in that office - attack plans, auror schedules, who is making the sandwiches and especially anything to do with our dear new Minister." It was perfect placement. A spy at one of the highest levels in the department.