Dangerous Passage, Southern Crimes Series by Lisa Harris and published by Revell Books.
When two Jane Does are killed on the outskirts of Atlanta, Georgia, detective and behavioral specialist Avery North discovers they share something in common-a tattoo of a magnolia on their shoulders. Suspecting a serial killer, Avery joins forces with medical examiner Jackson Bryant to solve the crimes and prevent another murder. But it doesn't take long for them to realize that there is much more to the case than meets the eye. As they venture deep into a sinister world of human trafficking, Avery and Jackson are taken to the very edge of their abilities-and their hearts.