There is another vat off to the left too, as it seems to them, and in it are some who during physical life thought they had done well when they had done wrong and vice versa. So they put evil in place of goodness. They stay there for a time, and all the while they are being deprived of their rationality. Once stripped of reason, they go into a kind of sleep, and they are not held responsible for anything they then do. They still seem to themselves to be awake, however.
When rationality returns to them, they regain consciousness and are like other spirits.
Out in front on the left is a room that holds no light, only pure darkness, which as a result is called the black room. The occupants are people who envied others their belongings and could not stop thinking about them. They stole without remorse whenever they could do so under a plausible pretext. Some there had been fairly prominent when they lived in the world and had honored duplicity as a mark of prudence. In the room they conspire with each other—as they had done while living in their bodies—about ways to deceive and defraud others. The darkness of the place delights them.
I was shown an image of the swindlers living there, in which I saw as clear as day what they eventually come to be like: their faces look worse than a dead person’s, as gray as that of a corpse, with horrible pockmarks, as they pass their time in a torment of anxiety.
from Secrets of Heaven, Volume 2, Sections 948, 949