Kingsley ignored the dig at the Aurors, and the taunt about contacting Dumbledore. If this man had wanted to bring this to Dumbledore, he would have. He had a reason for coming to the Aurors, and Kingsley was fairly sure it wasn't just to sling insults.
"There are plenty of glamours that last for quite awhile, and are very efficient this close up. That's the point of them, isn't it? Plus, that's not even taking into account permanent Transfiguration, or spells that alter perception." He raised an eyebrow at the warning, though he wasn't naive enough to discount the possible threat. "All right. Why don't you tell me what you know, and I'll decide from there what do about it, and about you."