Unnatural Exposure — Patricia Cornwell

A body is discovered in a Virginia landfill. The details--expert removal of head and limbs--mirror that of a case Dr. Kay Scarpetta has been investigating in Ireland. But for Scarpeita, the game has only just begun. The killer boldly contacts her via the Internet, signing off with the ominous screen name deadoc. As her investigation deepens, Scarpetta discovers that the victim in Virginia was exposed to a rare smallpox-like virus before she was killed, and that Scarpetta herself could be infected.

Now she knows she is up against a killer unlike any she has pursued before--a relentless psychopath with access to an incredibly sophisticated arsenal of deadly force. And with a very personal interest in seeing Kay Scarpetta suffer.