Nowhere safe
(Book)

Series numeration from Fantastic Fiction website.

She sense their twisted desires before she meets them. It's as if fate is helping her stop these monsters from preying on others the way she was preyed upon. And after she has delivered brutal justice, she will let the whole world see their guilt. "I must pay for what I've done." The first victim - naked, bound, frozen to death - wore the note strung around his neck. Now there's another note - this one attached to Detective September Rafferty's own stepbrother. Stefan survives, but September is sure he knows more than he's saying. Someone is eliminating suspected sexual predators, and the only thing more dangerous than a madman is a killer who's ruthlessly sane. Racing to predict the next target, September finds himself drawn into a harrowing and deeply personal case. For this time, there are no innocents - only the one who kills, and those condemned to die...