In the past when a great crime had been committed against the Dark Lord and the society he built, his faithful followers would use the opportunity to arrest as many suspected enemies of the regime as possible. Didn't matter if they weren't anywhere near the source of the crime. There weren't a great deal of civil rights within their country. Very little, in fact. What was the need for personal autonomy when the government was there to make certain you had all of your needs? Keeping the populace dependent on them for their survival was how the regime was able to pass through laws that stripped them from any remaining freedoms that still lingered. It was the Dark Lord's plan to one day smash out opposition and have an entire nation of witches and wizards who did exactly as he bid.