Lily Dawn FBI Suspense Thriller 03-Still Awake

FBI BAU Special Agent Lily Dawn, half Dutch, half Hispanic, raised in the Caribbean, knows the isles like the back of her hand.
When a surge in serial killers in the region prods the FBI to assemble a task force, Lily is the natural choice. But Lily is reluctant to face the demons of her past, including her missing sister, and when victims of a new serial killer appear at high end resorts on the Caribbean coast, it is up to Lily to uncover the truth.
Who is this killer targeting? And why?