The Survivor by Iris Johansen

Eve Duncan and Riley Smith must solve their most exciting puzzle since A Face to Die For when asked to uncover the mysterious secret hidden on a remote island.

When archeologist Riley Smith comes to ask Eve Duncan for help, Eve has to say no. Traveling halfway around the world on a dangerous quest is not her expertise as a forensic sculptor. But Eve is intrigued by the prospect of an isolated island that holds a secret locked in time.
Traveling to Southeast Asia, Riley is aware of the threat from treasure hunters who are already searching and have no qualms about killing to get what they want. When she successfully evades them and finds the perfectly preserved body of a female warrior, it is just what she needs to entice Eve to help unlock the mystery.
As these two strong women seek answers about this extraordinary past life, Riley makes a living, breathing discovery that will change history. If she can escape the island and survive long enough to share it with the world.