Wealth of Secrets by Stacy Angell Curtis

She thought her parents' deaths were an accident. Then a gunman broke into her home... In the wake of her parents’ sudden deaths, Brynnan’s reality is spinning out of control. Unexplained threats are dredging up past fears, and fueling new anxiety about her safety. Determined to help, Brynnan's billionaire uncle rushes to her side, along with his newly hired head-of-security—former special forces operative, Jack McKerrick. Jack is tasked with ensuring Brynnan’s safety, but when he' realizes she's being targeted, Jack learns about Brynnan’s painful past, and starts to suspect she’s in more danger than she realizes. Criminal activity, dating back to 19th century Texas, triggers the deadly course of events in the present that have Jack and Brynnan dodging bullets and praying they live to see justice served.