Stalked / by Brian Freeman.

Enhanced descriptions from Syndetics:

In Brian Freeman's thrilling novel Stalked , Lieutenant Jonathan Stride knows his partner Maggie Bei is in trouble when she reports a deadly crime on a bitter winter night. She's obviously hiding a terrible secret, and her silence only feeds suspicion. Maggie isn't the only one keeping secrets in Duluth. A seductive young woman has disappeared, leaving behind a stash of lurid fantasies and a cryptic message: I know who it is. Following a twisted trail, Stride uncovers a sordid web of violence and voyeurism that someone is willing to kill to keep hidden. Stride isn't alone. His lover Serena Dial - a homicide cop turned private investigator - is chasing a blackmailer who knows all the city's dirty secrets. Even Maggie's. But as Stride and Serena hunt for a killer, a predator with a vicious past is hunting them - with a terrifying plan for revenge. Now every step they take to expose the truth brings them closer to a showdown amid the howling winds of a winter storm. Where survival in the blinding snow is measured in seconds. Where crimes can be buried forever.