Germany had a similar issue in the 1930s when the German Communist Party (KPD) declared a holy war against German Christians and attempted a failed coup.

Everyone found guilty of participating in the failed communist coup were sentenced to serve time in prison.

Germany implemented strict checkpoints in a desperate attempt to round up the communists who escaped justice.

The difference was the German Christians trusted their government and were thankful they were able to survive the communist coup.

This is why communists, especially (ahem) "Bolsheviks" hate the "papers please" because that's likely what we'll be forced to do before this is over.