Wings in the Night

From the introduction:

It is September of 1892 and Dracula has built up his power base. He has gathered influence since his arrival during the summer, with power over major businessmen and even perhaps a few Members of Parliament, as well as some status in the underworld. He has social status, friends and connections, and none of these associates realize more than a hint of his unusual nature. He also has spies and agents planted in the government and around the city. However, his covert nocturnal activities have roused interest, though not yet connected to him. A semi-secret, informal Special Inquiry Board has been commissioned by the Home Secretary.