Shrike by Jeff Carlson

Set in present-day Raleigh, North Carolina, Shrike is the story of one young woman's overcoming tremendous physical, emotional and logistical adversity to defeat evil incarnate. When Taryn Spire and her best friend learn that some banking executives plan a cybercrime to embezzle funds from the North Carolina State Fair, the adventure begins. A botched attempt by the perpetrators to silence them permanently leads to a dramatic transformation for Taryn - watching a television program featuring a video clip of a shrike with its prey destines her to become a crime fighter. With the help and the love of an unlikely ally (a motorcycle salesman), Taryn, as her alter ego, dispenses a unique type of justice.