Not quite a fortnight ago, eight Death Eaters in the maximum-security wing of Azkaban Prison were killed during the night. All of the Death Eaters’ cell doors, which only can be opened by using the "Snakestone" (a runestone that speaks snake-language), were opened somehow, and Dementors swooped in and Kissed the Death Eaters. The prison wards didn’t notice anyone sneaking into the prison that night, nor did the wards notice anyone leaving the prison that night.