The Vampire Man — Gerald Verner

Conway Jackson, amateur criminologist, receives a disturbing letter from his uncle, Sir James Gleeson, informing him that he feels himself to be in terrible danger, and imploring him to come to his country manor. Unfortunately, the letter has taken some time to reach him, and it shows unmistakable signs of having been steamed open. On his arrival, Jackson learns that his uncle was found strangled in his bedroom the night before - by what appears to be an inhuman monster that is destined not to stop at a single victim...