Detachment Fault

Description for DETACHMENT FAULT by Susan Cummins Miller:

As a geologist, Frankie MacFarlane is a dedicated student of the earth -- its changes, its movements, and its power. Now, she must use her deductive skills to uncover a mystery below the calm surface of her native Tucson, Arizona...

After laboring long and hard on field research for her Ph.D., Frankie joins her brother and his girlfriend Carla on a relaxing fishing trip. There, they reel in a catch they wish they could throw back: the body of a faceless man. With this shocking discovery, their holiday is over -- but then Carla disappears, and they realize that their troubles are only beginning.

Back in Tucson two weeks later, one of Frankie's students is murdered, and she's wearing the same rare alexandrite ring Carla had on when Frankie last saw her. Then a fellow professor is killed, and Frankie realizes these crimes are all connected. But it's going to take a lot of time -- and the application of serious pressure at the weak points -- to break this case open...

This is #2 in The Second Of The Frankie MacFarlane Mysteries.