Shadow of Fear by Susan Sleeman

To catch a killer…
Forensic engineer Kinsley Pierce is used to dispassionately digging into building and structure failures to determine the cause of the failure. But when she starts receiving disturbing death threats, she’s anything but dispassionate. Fearing for her life, she runs to the one place she’s always felt safe. Her hometown, Shadow Lake. But she never expected her best friend’s bossy brother to steamroll in and take over her protection.

Will he work outside the law?
Former deputy Devon (Dev) Graham now team member at Shadow Lake Survival insists Kinsley move to the company’s compound for her own safety. He could do nothing else. As a former deputy, he spent most of his adult life protecting others. He also spent years ignoring his attraction to his little sister’s best friend. He will never marry, and his sister would never forgive him if he led Kinsley on only to hurt her. Too bad. He would just have to ignore his feelings. She’s in danger, and he’s the one to watch over her. Whatever the risk. Whatever it takes. Even when they head down an upsetting path of betrayal and false trails that lead to a grisly death, he’ll protect Kinsley with his own life until the killer threatening her is behind bars.