EWTN Catholic Q&A
Satan reign
Question from buffermop on 12-28-2012:

Is Satan allowed to spread his evil practices in Purgatory?

Answer by Fr. John Echert on 01-02-2013:

The souls of Purgatory are assured salvation and it will nor be taken from them. They suffer, especially in awaiting the vision of God and regret for their sins. So I am inclined to view that the souls of Purgatory are unmolested by devils.

father Echert