Shark Cove by Toby Neal

Danger lurks in paradise.
The past never stays buried.

Sixteen years ago, Sergeant Lei Texeira met Harriet Vierra and Malia, the infant she adopted, in a deadly encounter in Mexico. Now a detective with the Maui Police Department, Harry works with Lei, and Malia, a teen sleuth, is determined to find her lost friend Camille.

But Camille is only one of many missing girls.

Young women are vanishing across the islands without a trace. Lei and Harry search for answers with the FBI, as Malia secretly conducts her own dangerous investigation: but for the girls taken by traffickers, time is running out.