Rulers of Darkness by Steven Spruill

"It is midnight at the historic Washington Cathedral when police discover the murdered woman--her throat shredded by human teeth. When other such murders follow, Dr. Katherine O'Keefe and her ex-lover, Detective Merrick Chapman are assigned to track down the "vampire" killer. They discover a bizarre abnormality in the killer's blood. The man is stricken with a rare disease whereby the blood genetically craves infusions of fresh blood. It is a condition Merrick knows well--because he too has it. And as O'Keefe and Chapman draw closer to the killer, they may find a truth more horrific than the murders themselves." (from Amazon.com)

Paperback Info: ISBN 0312956681, St Martins, 1998

More by Steven Spruill: Daughter of Darkness