User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-104.7.80.176-20150312123401/@comment-24502975-20150312174342

^It was mentioned in volume 17 that some of the officials who police Tokyo are aware of the existence of supernatural beings or something like that. Entering the Vampire's territory has nothing to do with that though. IIRC they used several transportation magic circles and then a car.