The witness / Nora Roberts.

Enhanced descriptions from Syndetics:

Daughter of a controlling mother, Elizabeth finally let loose one night, drinking at a nightclub and allowing a strange man's seductive Russian accent lure her to a house on Lake Shore Drive. The events that followed changed her life forever.

Twelve years later, the woman known as Abigail Lowery lives on the outskirts of a small town in the Ozarks. A freelance programmer, she designs sophisticated security  systems--and supplements her own security with a fierce dog and an assortment of firearms. She keeps to herself, saying little, revealing nothing. But Abigail's reserve only intrigues police chief Brooks Gleason. Her logical mind, her secretive nature, and her unromantic viewpoints leave him fascinated but frustrated. He suspects that Abigail needs protection from something--and that her elaborate defenses hide a story that must be revealed.

With a quirky, unforgettable heroine and a pulse-pounding plotline, Nora Roberts presents a riveting new read that cements her place as today's most reliably entertaining thriller
author--and will leave people hungering for more.