The Least of These (The Detective Abbey Rhodes Mysteries) by Mitchell S Karnes

Nashville Homicide Detective Abbey Rhodes is caught between a high-profile murder and multiple disappearances in a homeless camp. When the Mayor discovers one of the victims is the stepson of Jonathan Lee Thomas, a wealthy investor in the city's East Bank Project, he forces Abbey to abandon all other cases but his. She faithfully follows orders until her best friend missing.

Abbey stretches herself to the limit as she learns every life has value. Her investigation jeopardizes the safety of her closest friends, and Abbey must face her guilt when one of them is shot. As the body count grows, each death triggers Abbey's PTSD, dredging up the past and its secrets, and her carefully crafted protective walls come crashing down around her.