Msgr. Rossetti

Response:
This is an important question regarding infestation of a place as well as with cases of possession/oppression. How do we know if a possessed person is totally freed? How do we know if the demons have completely left a place?

Fr. Gabriel Amorth once said that the Exorcist cannot be sure that someone is fully liberated except by waiting for an extended period of time, I believe he said up to a year, and checking to see if the person is symptom-free. In addition, the Exorcist can pray over the person every so often to check for a demonic presence and reaction.

Similarly, one cannot be certain that an infested location has been fully cleansed unless there is an extended period of time of the location being symptom-free. Certainly there are initial signs a possessed person has possibly been liberated— the person may scream and then a calm ensues with the person reporting feeling liberated. But this can be only a partial liberation and/or the demons can be trying to fool the Exorcist into believing they have fully left. This is a very common demonic tactic. So we continue to wait, watch and test the waters.