Shadow Over Bright Star — Irene M. Pascoe

'Died in an accident.' The terse words were scrawled on a returned letter that Jessica Winsor had sent to her father. Aghast, she journeyed to Virginia City to investigate, and was stunned to learn that she was suddenly very wealthy. Her father had willed her his majority share of a silver mine. But the mine had two other shareholders -- Derek and Brett Bonner, cousins now faced with losing what they'd thought was theirs alone. Jessica found herself inexorably drawn to the enigmatic Derek, but when she experienced several 'accidents' she knew it was a deadly attraction.