Certain prey - John Sandford

Clara Rinker is a Southern woman, pleasant, attractive - and the best hitwoman in the business. She isn't showy; she just goes about her business, collects her money and goes home. It's when she's hired for a job in Minnesota that things become complicated. A defense attorney wants a rival eliminated, and that's fine. But then a witness survives, the attorney starts acting weird, this big cop Davenport gets on her case, and loose ends begin popping up faster than a sweater unravelling. Clara hates loose ends, and she only knows one way of dealing with them: you start cutting them off until they're all gone. Suddenly Davenport is up against the most ruthlessly intelligent killer he's ever faced.