The logical outcome of this kind of predatory practice should be that the "investor" (the purchaser of the liens) gets $5000 out of the $197,000 sale, and the debtor gets $192,000. And even that seem predatory, never mind getting all the equity and forcing the person out of their place of residence.
I have a hard time believing this story. If it actually is true, the local government in DC is beyond corrupt.
That might be part of the problem... they really don't have much local government. Congress holds sway in DC. When I lived in Glover Park I thought it was one of the strangest systems I had ever seen. Never really quite understood it completely.